diff --git a/docker/dep/Dockerfile b/docker/dep/Dockerfile
index bf2d0d65bb..bbc0c44d41 100644
--- a/docker/dep/Dockerfile
+++ b/docker/dep/Dockerfile
@@ -13,8 +13,7 @@ ADD https://github.com/krallin/tini/releases/download/${TINI_VERSION}/tini /tini
 RUN chmod +x /tini
 
 # setup environment
-RUN locale-gen en_US.UTF-8
-ENV LANG en_US.UTF-8
+ENV LANG C.UTF-8
 
 # add Paparazzi PPA
 RUN DEBIAN_FRONTEND=noninteractive apt-get update && apt-get install -y software-properties-common