diff --git a/.github/workflows/bump-version.yml b/.github/workflows/bump-version.yml
index 51ad0f4c..83bf298d 100644
--- a/.github/workflows/bump-version.yml
+++ b/.github/workflows/bump-version.yml
@@ -32,7 +32,6 @@ on:
       - environment-dev.yml
       - environment.yml
       - pyproject.toml
-      - setup.py
       - src/xscen/__init__.py
       - templates
       - tests/*.py
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index c73b6a25..1be002f4 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -9,8 +9,6 @@ on:
       - CHANGELOG.rst
       - README.rst
       - pyproject.toml
-      - setup.cfg
-      - setup.py
       - xscen/__init__.py
   pull_request:
 
@@ -91,11 +89,7 @@ jobs:
             esmf=${{ env.esmf-version }}
             mamba
             python=${{ matrix.python-version }}
-            babel
             tox
-      - name: Compile catalogs
-        run: |
-          make translate
       - name: Test with tox
         run: |
           python -m tox -e ${{ matrix.tox-build }}
@@ -104,9 +98,6 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           COVERALLS_FLAG_NAME: run-Python${{ matrix.python-version }}
 
-  #      - name: Compile language catalogs
-#        run: |
-#          make translate
 #      - name: Install esmpy
 #        run: |
 #          pip install git+https://github.com/esmf-org/esmf.git@v${{ matrix.esmf-version }}#subdirectory=src/addon/esmpy
diff --git a/.github/workflows/publish-pypi.yml b/.github/workflows/publish-pypi.yml
index 8427f5e4..69a70300 100644
--- a/.github/workflows/publish-pypi.yml
+++ b/.github/workflows/publish-pypi.yml
@@ -35,10 +35,9 @@ jobs:
           python-version: "3.x"
       - name: Install packaging libraries
         run: |
-          python -m pip install babel build setuptools wheel
+          python -m pip install build setuptools wheel
       - name: Build a binary wheel and a source tarball
         run: |
-          make translate
           python -m build --sdist --wheel
       - name: Publish distribution 📦 to PyPI
         uses: pypa/gh-action-pypi-publish@ec4db0b4ddc65acdf4bff5fa45ac92d78b56bdf0 # v1.9.0
diff --git a/.github/workflows/tag-testpypi.yml b/.github/workflows/tag-testpypi.yml
index 867f7496..006dd230 100644
--- a/.github/workflows/tag-testpypi.yml
+++ b/.github/workflows/tag-testpypi.yml
@@ -59,10 +59,9 @@ jobs:
           python-version: "3.x"
       - name: Install packaging libraries
         run: |
-          python -m pip install babel build setuptools wheel
+          python -m pip install build setuptools wheel
       - name: Build a binary wheel and a source tarball
         run: |
-          make translate
           python -m build --sdist --wheel
       - name: Publish distribution 📦 to Test PyPI
         uses: pypa/gh-action-pypi-publish@ec4db0b4ddc65acdf4bff5fa45ac92d78b56bdf0 # v1.9.0
diff --git a/.github/workflows/upstream.yml b/.github/workflows/upstream.yml
index 3da6f88a..d3f25db1 100644
--- a/.github/workflows/upstream.yml
+++ b/.github/workflows/upstream.yml
@@ -8,8 +8,6 @@ on:
       - CHANGELOG.rst
       - README.rst
       - pyproject.toml
-      - setup.cfg
-      - setup.py
       - xscen/__init__.py
   schedule:
     - cron: "0 0 * * *" # Daily “At 00:00” UTC
diff --git a/.gitignore b/.gitignore
index f5bcdf03..36c14155 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,6 +11,9 @@ docs/notebooks/samples/example*
 docs/notebooks/samples/gs-weights/
 !docs/notebooks/samples/tutorial/*/*/*/*/*/*/*/*.nc
 
+# Translation stuff
+*.pot
+
 # Byte-compiled / optimized / DLL files
 __pycache__/
 *.py[cod]
@@ -61,10 +64,6 @@ coverage.xml
 .hypothesis/
 .pytest_cache/
 
-# Translations
-*.mo
-*.pot
-
 # Django stuff:
 *.log
 local_settings.py
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 1fd38857..a8de3b16 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -11,9 +11,7 @@ repos:
     rev: v4.6.0
     hooks:
       - id: trailing-whitespace
-        exclude: setup.cfg
       - id: end-of-file-fixer
-        exclude: setup.cfg
       - id: debug-statements
       - id: mixed-line-ending
       - id: check-json
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index ef43a327..703513c8 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -20,6 +20,7 @@ Internal changes
 * Added pins to `xarray`, `xclim`, `h5py`, and `netcdf4`. (:pull:`414`).
 * Add ``.zip`` and ``.zarr.zip`` as possible file extensions for Zarr datasets. (:pull:`426`).
 * Explicitly assign coords of multiindex in `xs.unstack_fill_nan`. (:pull:`427`).
+* French translations are compiled offline. A new check ensures no PR are merged with missing messages. (:issue:`342`, :pull:`443`).
 
 v0.9.1 (2024-06-04)
 -------------------
diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index b8ead9d5..6c0280dc 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -203,7 +203,7 @@ Once the code is implemented and translatable strings are marked as such, we nee
 
     $ make findfrench
 
-Then go edit ``xscen/xscen/data/fr/LC_MESSAGES/xscen.po`` with the correct French translations. Finally, running::
+Then go edit ``xscen/xscen/data/fr/LC_MESSAGES/xscen.po`` with the correct French translations. Finally, run::
 
     $ make translate
 
diff --git a/MANIFEST.in b/MANIFEST.in
index 75611f22..070cdb41 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -5,15 +5,13 @@ include LICENSE
 include Makefile
 include README.rst
 include pyproject.toml
-include setup.cfg
-include setup.py
 include .zenodo.json
 
 recursive-include src/xscen *.py *.yml
 recursive-include src/xscen/CVs *.json
 recursive-include src/xscen/data/fr *.yml *.csv
 recursive-include src/xscen/data *.nc
-recursive-include src/xscen/data/fr/LC_MESSAGES *.mo *.po
+recursive-include src/xscen/data *.mo *.po
 recursive-include tests *.py
 recursive-include docs conf.py Makefile make.bat *.png *.rst *.yml
 recursive-include docs/locales *.mo *.po
diff --git a/Makefile b/Makefile
index b4db756a..7beb153c 100644
--- a/Makefile
+++ b/Makefile
@@ -110,8 +110,15 @@ dev: clean ## install the package in editable mode with all development dependen
 	pre-commit install
 
 findfrench:  ## Extract phrases and update the French translation catalog (this doesn't translate)
-	python setup.py extract_messages
-	python setup.py update_catalog -l fr
+	pybabel extract -o src/xscen/data/messages.pot --omit-header --input-dirs=src/xscen/
+	pybabel update -l fr -D xscen -i src/xscen/data/messages.pot -d src/xscen/data/ --omit-header
 
 translate:   ## Compile the translation catalogs.
-	python setup.py compile_catalog
+	pybabel compile -f -D xscen -d src/xscen/data/
+
+checkfrench:  ## Error if the catalog could be update or if the compilation is older than the catalog.
+	rm -f .check_messages.pot
+	pybabel extract -o .check_messages.pot --omit-header --input-dirs=src/xscen/
+	pybabel update -l fr -D xscen -i .check_messages.pot -d src/xscen/data/ --omit-header --check
+	rm -f .check_messages.pot
+	if [ src/xscen/data/fr/LC_MESSAGES/xscen.mo -ot src/xscen/data/fr/LC_MESSAGES/xscen.po ]; then echo "Compilation is older than translations. Please compile with 'make translate'."; exit 1; fi
diff --git a/environment-dev.yml b/environment-dev.yml
index 149a058f..1e3332af 100644
--- a/environment-dev.yml
+++ b/environment-dev.yml
@@ -3,7 +3,7 @@ channels:
   - conda-forge
 dependencies:
   - python >=3.9,<3.13
-  # Don't forget to sync changes between environment.yml, environment-dev.yml, and setup.py!
+  # Don't forget to sync changes between environment.yml, environment-dev.yml, and pyproject.toml!
   # Also consider updating the list in xs.utils.show_versions if you add a new package.
   # Main packages
   - cartopy >=0.23.0
diff --git a/environment.yml b/environment.yml
index 8d2d86e0..5b98d8f4 100644
--- a/environment.yml
+++ b/environment.yml
@@ -3,7 +3,7 @@ channels:
   - conda-forge
 dependencies:
   - python >=3.9,<3.13
-  # Don't forget to sync changes between environment.yml, environment-dev.yml, and setup.py!
+  # Don't forget to sync changes between environment.yml, environment-dev.yml, and pyproject.toml!
   # Also consider updating the list in xs.utils.show_versions if you add a new package.
   # Main packages
   - cartopy >=0.23.0
@@ -33,8 +33,7 @@ dependencies:
   - xclim >=0.50, <0.51
   - xesmf >=0.7
   - zarr
-  # To install from source and get translations
-  - babel
+  # To install from source
   - setuptools >=65.0.0
   - setuptools-scm >=8.0.0
   # Opt
diff --git a/pyproject.toml b/pyproject.toml
index 446547ab..7e7c3623 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -2,7 +2,6 @@
 requires = [
   "setuptools >=65.0.0",
   "setuptools-scm >=8.0",
-  "babel",
   "wheel"
 ]
 build-backend = "setuptools.build_meta"
@@ -35,7 +34,6 @@ classifiers = [
 ]
 dynamic = ["version"]
 dependencies = [
-  "babel",
   "cartopy >=0.23.0",
   "cftime",
   "cf_xarray >=0.7.6",
@@ -71,6 +69,7 @@ dependencies = [
 dev = [
   # Dev tools and testing
   "pip >=23.3.0",
+  "babel",
   "black[jupyter] ==24.4.2",
   "blackdoc ==0.3.9",
   "bump-my-version >=0.18.3",
@@ -286,8 +285,6 @@ include = ["xscen"]
 # "docs/notebooks/samples/*.yml",
 # "environment.yml",
 # "environment-dev.yml",
-# "setup.cfg",
-# "setup.py",
 # "src/xscen/**/*.py",
 # "src/xscen/**/*.yml",
 # "src/xscen/CVs/*.json",
diff --git a/setup.cfg b/setup.cfg
deleted file mode 100644
index 34d9e7ba..00000000
--- a/setup.cfg
+++ /dev/null
@@ -1,17 +0,0 @@
-[extract_messages]
-output_file = xscen.pot
-keywords = _ gettext ngettext
-
-[init_catalog]
-domain = xscen
-input_file = xscen.pot
-output_dir = src/xscen/data
-
-[update_catalog]
-domain = xscen
-input_file = xscen.pot
-output_dir = src/xscen/data
-
-[compile_catalog]
-domain = xscen
-directory = src/xscen/data
diff --git a/setup.py b/setup.py
deleted file mode 100644
index 127a38be..00000000
--- a/setup.py
+++ /dev/null
@@ -1,25 +0,0 @@
-"""Custom installation process for xscen translations."""
-
-from babel.messages.frontend import compile_catalog
-from setuptools import setup
-from setuptools.build_meta import *  # noqa: F403, F401
-from setuptools.command.install import install
-
-
-class InstallWithCompile(install):
-    """Injection of the catalog compilation in the installation process."""
-
-    def run(self):
-        """Install the package, but compile the i18n catalogs first."""
-        compiler = compile_catalog(self.distribution)
-        option_dict = self.distribution.get_option_dict("compile_catalog")
-        compiler.domain = [option_dict["domain"][1]]
-        compiler.directory = option_dict["directory"][1]
-        compiler.run()
-        super().run()
-
-
-setup(
-    cmdclass={"install": InstallWithCompile},
-    message_extractors={"xscen": [("**.py", "python", None)]},
-)
diff --git a/src/xscen/data/fr/LC_MESSAGES/xscen.mo b/src/xscen/data/fr/LC_MESSAGES/xscen.mo
new file mode 100644
index 00000000..0c1c2619
Binary files /dev/null and b/src/xscen/data/fr/LC_MESSAGES/xscen.mo differ
diff --git a/src/xscen/data/fr/LC_MESSAGES/xscen.po b/src/xscen/data/fr/LC_MESSAGES/xscen.po
index e7d76e0a..027dae3f 100644
--- a/src/xscen/data/fr/LC_MESSAGES/xscen.po
+++ b/src/xscen/data/fr/LC_MESSAGES/xscen.po
@@ -1,51 +1,32 @@
-# French translations for xscen.
-# Copyright (C) 2023 ORGANIZATION
-# This file is distributed under the same license as the xscen project.
-# Équipe Xscen <Rondeau-Genesse.Gabriel@ouranos.ca>, 2023.
-#
-msgid ""
-msgstr ""
-"Project-Id-Version: xscen 0.6.18b0\n"
-"Report-Msgid-Bugs-To: Rondeau-Genesse.Gabriel@ouranos.ca\n"
-"POT-Creation-Date: 2023-09-29 11:45-0400\n"
-"PO-Revision-Date: 2023-08-15 16:48-0400\n"
-"Last-Translator: Pascal Bourgault <bourgault.pascal@ouranos.ca>\n"
-"Language: fr\n"
-"Language-Team: fr <LL@li.org>\n"
-"Plural-Forms: nplurals=2; plural=(n > 1);\n"
-"MIME-Version: 1.0\n"
-"Content-Type: text/plain; charset=utf-8\n"
-"Content-Transfer-Encoding: 8bit\n"
-"Generated-By: Babel 2.12.1\n"
-
-#: xscen/aggregate.py:185
-msgid "{window}-year mean of {attr}."
+#: src/xscen/aggregate.py:435
+#, fuzzy
+msgid "{window}-year climatological {operation} of {attr}."
 msgstr "Moyenne {window} ans de {attr}."
 
-#: xscen/aggregate.py:319
+#: src/xscen/aggregate.py:649
 msgid "{attr1}: {kind} delta compared to {refhoriz}."
 msgstr "{attr1}: Delta {kind} comparé à {refhoriz}."
 
-#: xscen/diagnostics.py:501
+#: src/xscen/diagnostics.py:522
 msgid "Ranking of measure performance"
 msgstr "Classement de performance de la mesure"
 
-#: xscen/diagnostics.py:560
+#: src/xscen/diagnostics.py:581
 msgid "Fraction of improved grid cells"
 msgstr "Fraction de points de grille améliorés"
 
-#: xscen/io.py:650
+#: src/xscen/io.py:761 src/xscen/io.py:769
 msgid "Variable"
 msgstr "Variable"
 
-#: xscen/io.py:650
+#: src/xscen/io.py:762
 msgid "Description"
 msgstr "Description"
 
-#: xscen/io.py:650
+#: src/xscen/io.py:765
 msgid "Units"
 msgstr "Unités"
 
-#: xscen/io.py:654
+#: src/xscen/io.py:770
 msgid "Content"
 msgstr "Contenu"
diff --git a/tox.ini b/tox.ini
index 33eea6c9..fd3425f9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,7 +5,6 @@ envlist =
     py{39,310,311,312}
     docs-esmpy
 requires =
-    babel
     pip >= 23.3.0
     setuptools >= 65.0
 opts =
@@ -13,12 +12,13 @@ opts =
     --verbose
 
 [testenv:lint]
-description = Check for Code Compliance
+description = Check for Code Compliance and missing french translations
 skip_install = True
 download = true
 conda_channels =
 conda_env =
 deps =
+    babel
     black[jupyter] ==24.4.2
     blackdoc ==0.3.9
     isort ==5.13.2
@@ -30,6 +30,7 @@ commands_pre =
     pip list
 commands =
     make lint
+    make checkfrench
 allowlist_externals =
     make