diff --git a/lib/Properties.hs b/lib/Properties.hs
index 05020f56fa8ac8192fef723aeef14d1efb057695..94cfe2469dd9c258f14e188e6051a028a4232d93 100644
--- a/lib/Properties.hs
+++ b/lib/Properties.hs
@@ -135,7 +135,7 @@ checkTileset = do
 
   -- reject tilesets unsuitable for workadventure
   unless (tilesetTilewidth tileset == 32 && tilesetTileheight tileset == 32)
-    $ complain "Tilesets must have tile size 32×32."
+    $ complain "Tilesets must have tile size 32x32."
 
   unless (tilesetImageheight tileset < 4096 && tilesetImagewidth tileset < 4096)
     $ warn "Tilesets should not be larger than 4096x4096 pixels in total."