Last night on the topic of #traduc on irc.oftc.net, the topic mentioned the following URL:
In French typo we have non-breakable spaces. The problem is that currently mozilla does not handle these non-breakable spaces correclty. It simply replaces non-breakable spaces by “normal” spaces. It renders some forms, filenames and wiki very dirty. You could help solving this issue by voting for this bug.
For more information, read the whole bug repport. Please VOTE for this bug!