The best croissants I have ever had (when fresh). Their kouign Amman is also amazing. I typically don't like heavy desserts but it is perfectly balanced.
The only thing holding it from five stars is that there is no seating and if the time you visit isn't good (too late in the day, right after a holiday) the croissants won't be fresh and thus very average and there won't be any kouign Amman left.
Go early in the day though, and you will be in for a delicious treat!