diff --git a/Dockerfile b/Dockerfile
index 885fe14..b13ff1a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -13,12 +13,6 @@ RUN apt update && \
     docker-php-ext-install gettext && \
     rm -rf /var/lib/apt/lists/*
 
-RUN sed -i "/$DEFAULT_LANGUAGE/s/^# //g" /etc/locale.gen && \
-    locale-gen
-ENV LANG $DEFAULT_LANGUAGE
-ENV LANGUAGE $DEFAULT_LANGUAGE
-ENV LC_ALL $DEFAULT_LANGUAGE
-
 COPY . /usr/local/signaturepdf
 
 RUN envsubst < /usr/local/signaturepdf/config/php.ini > /usr/local/etc/php/conf.d/uploads.ini && \
diff --git a/README.md b/README.md
index d8b8416..50bc084 100644
--- a/README.md
+++ b/README.md
@@ -81,15 +81,16 @@ docker run -d --name=signaturepdf -p 8080:80 signaturepdf
 
 The following variables can be used to configure the deployment:
 
-| Variable               | description                                                           | exemple                          | defaut    |
-| ---------------------- |-----------------------------------------------------------------------| -------------------------------- | --------- |
-| `SERVERNAME`           | Deployment URL                                                        | `pdf.24eme.fr`                   | localhost |
-| `UPLOAD_MAX_FILESIZE`  | Maximum size of the PDF file to sign                                  | 48M                              | 24M       |
-| `POST_MAX_SIZE`        | Maximum size of the PDF file to sign                                  | 48M                              | 24M       |
-| `MAX_FILE_UPLOADS`     | Maximum number of pages in the PDF, here 200 pages + the original PDF | 401                              | 201       |
-| `PDF_STORAGE_PATH`     | Path where uploaded PDF files can be stored                           | /data                            | /data     |
-| `DISABLE_ORGANIZATION` | Disable the Organize route                                            | true                             | false     |
-| `PDF_DEMO_LINK`        | Show, hide, or change the demo PDF link                               | false, `link` or `relative path` | true      |
+| Variable               | description                                                           | exemple                          | defaut      |
+|------------------------|-----------------------------------------------------------------------|----------------------------------|-------------|
+| `SERVERNAME`           | Deployment URL                                                        | `pdf.24eme.fr`                   | localhost   |
+| `UPLOAD_MAX_FILESIZE`  | Maximum size of the PDF file to sign                                  | 48M                              | 24M         |
+| `POST_MAX_SIZE`        | Maximum size of the PDF file to sign                                  | 48M                              | 24M         |
+| `MAX_FILE_UPLOADS`     | Maximum number of pages in the PDF, here 200 pages + the original PDF | 401                              | 201         |
+| `PDF_STORAGE_PATH`     | Path where uploaded PDF files can be stored                           | /data                            | /data       |
+| `DISABLE_ORGANIZATION` | Disable the Organize route                                            | true                             | false       |
+| `PDF_DEMO_LINK`        | Show, hide, or change the demo PDF link                               | false, `link` or `relative path` | true        |
+| `DEFAULT_LANGUAGE`     | Default language for the application                                  | en_US.UTF-8                      | fr_FR.UTF-8 |
 
 ```bash
 docker run -d --name=signaturepdf -p 8080:80 -e SERVERNAME=pdf.example.org -e UPLOAD_MAX_FILESIZE=48M -e POST_MAX_SIZE=48M -e MAX_FILE_UPLOADS=401 -e PDF_STORAGE_PATH=/data signaturepdf
diff --git a/app.php b/app.php
index d8afe06..1e0baed 100644
--- a/app.php
+++ b/app.php
@@ -5,7 +5,7 @@ setlocale(LC_ALL, "");
 $f3 = require(__DIR__.'/vendor/fatfree/base.php');
 
 $f3->set('FALLBACK', null);
-$f3->language($f3->get('HEADERS')['Accept-Language']);
+$f3->language(isset($f3->get('HEADERS')['Accept-Language']) ? $f3->get('HEADERS')['Accept-Language'] : '');
 
 session_start();
 
diff --git a/entrypoint.sh b/entrypoint.sh
index 67a372a..f8d5caf 100755
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -4,6 +4,12 @@ envsubst < /usr/local/signaturepdf/config/apache.conf > /etc/apache2/sites-avail
 envsubst < /usr/local/signaturepdf/config/php.ini > /usr/local/etc/php/conf.d/uploads.ini
 envsubst < /usr/local/signaturepdf/config/config.ini.tpl > /usr/local/signaturepdf/config/config.ini
 
+sed -i "/$DEFAULT_LANGUAGE/s/^# //g" /etc/locale.gen && locale-gen
+export LANG=$DEFAULT_LANGUAGE
+export LANGUAGE=$DEFAULT_LANGUAGE
+export LC_ALL=$DEFAULT_LANGUAGE
+
+
 if [[ ! -z $PDF_STORAGE_PATH ]] ; then
     mkdir -p $PDF_STORAGE_PATH
     chown www-data:www-data $PDF_STORAGE_PATH