@hatbang @noiob I renamed it with the file manager, so there shouldn't be an issue anymore. Even took out all the special french characters. Still isn't showing the new files. (all renaming was done by GUI, sorry ^ ^)
Solved it by creating a new folder and cp-ing the files inside that. that worked.
permissions are all -rw-rw-r-- and I am the owner. (same as for the one, older file it is showing). so weird. maybe I should try to reproduce that and file a bug? but not now :D
@noiob @jollysea I‘d also say check what happens if you mv or cp it to a new name. If that stays an issue my next guess would be a permission issue that makes gnome ignore the files owned by the user of that file