diff --git a/build/bench/Dockerfile b/build/bench/Dockerfile
index 7c58114d..78a2381c 100644
--- a/build/bench/Dockerfile
+++ b/build/bench/Dockerfile
@@ -48,6 +48,9 @@ RUN install_packages \
     python3-tk \
     python-virtualenv
 
+RUN sed -i -e 's/# en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/' /etc/locale.gen \
+  && dpkg-reconfigure --frontend=noninteractive locales
+
 # Install wkhtmltox correctly
 RUN wget https://github.com/wkhtmltopdf/wkhtmltopdf/releases/download/0.12.5/wkhtmltox_0.12.5-1.stretch_amd64.deb
 RUN dpkg -i wkhtmltox_0.12.5-1.stretch_amd64.deb && rm wkhtmltox_0.12.5-1.stretch_amd64.deb