diff --git a/flask_app/__init__.py b/flask_app/__init__.py
index 473c4d7..4ce2848 100644
--- a/flask_app/__init__.py
+++ b/flask_app/__init__.py
@@ -43,7 +43,7 @@ def parse_authorized_response(resp):
     print(type(resp))
     print(resp)
     if resp is None:
-        return 'Access denied: reason=%s error=%s' % (
+        return 'Access denied: reason={0!s} error={1!s}'.format(
             request.args['error_reason'],
             request.args['error_description']
         )
diff --git a/flask_app/controller.py b/flask_app/controller.py
index efb2e3b..6e35add 100644
--- a/flask_app/controller.py
+++ b/flask_app/controller.py
@@ -4,4 +4,4 @@
 
 @fapp.route('/<page>', defaults={'page': 'index'})
 def main(page):
-    return render_template('pages/%s.html' % page)
+    return render_template('pages/{0!s}.html'.format(page))