diff --git a/radicale/Dockerfile b/radicale/Dockerfile
index 253f0d8..fc9a00b 100644
--- a/radicale/Dockerfile
+++ b/radicale/Dockerfile
@@ -1,5 +1,9 @@
 FROM debian:jessie
 
+# http://bugs.python.org/issue19846
+# > At the moment, setting "LANG=C" on a Linux system *fundamentally breaks Python 3*, and that's not OK.
+ENV LANG C.UTF-8
+
 ENV VERSION 2.1.2
 
 # Install dependencies