There is some generalization here that's not very appropriate and a perfume...
I can tell you that a lot of French employees are working more than those 35h/week (depending on their position and/or if they want to earn more). Don't see French people as idle loafers while you are doing all the hard work !
You are not employed by this French company to compensate the hours "not worked" by their French employees but because your salary is so competitive for these entry-level jobs that communication and time difference issues can be accepted (and are maybe also some of the reasons you're working more). FYI, the minimum wage in France ~$20500/year.
Don't you have breaks (lunch) ?! If you feel (are) indeed exploited then you and your colleagues should take appropriate actions to improve your working conditions.