Report your bugs here - if someone else has already mentioned the same bug, just add on to their post with as much info as possible to make the hunting easier.
I'll live with it (I made far too many modifications to want to trash it all and reimport at some future time now), but I thought I had to report the issue
Unfortunately, DL makes the cover images part of their database file making the file quite large to send or to handle in anyway that would be practical. Thank you for beta testing that. Sadly I can't repeat it, using your text in title and comments and summary "Après le triomphe de L'Auberge espagnole, Cédric Klapisch a choisi de s'essayer à un genre très codifié du film noir", comes across perfectly in the import. I tired a few extra such as illustrator and genre and those also work. Since you have already made modifications and won't be importing it again I'll put it on the known bug list and wait to see if it crops up again for another user. Thank you.