Are you basing this on past experience or more from a "French Bashing" point of view, because it seems to me it is the latter.
Renault -Nissan share many of the same parts and platforms and Nissan's reliability and quality is not poor and I don't think the newer Renaults are any worse. I have friends that own Peugeots and they are very happy with them. I recently drove and spent some time in their 508 and I can tell you that the interior fit and finish (materials used, etc.) was better than my much more expensive 2010 C class Mercedes. While it can be said the the quality of French cars has been up and down since they their existence, so has many other brands.
German cars have built a reputation on superior engineering but they certainly don't have superior long term reliability (or quality). A shinny, pretty penny is just a shinny, pretty penny on the outside and what really counts is what is on the inside...
I have owned several high end German luxury cars - BMW and Mercedes Benz and I can tell you that while pretty, shinny and generally good driving cars, they have woeful long term reliability, especially right when basic warranty expires. It seems that most parts are just engineered to last that long (50K or less) and both brands including Audi and Volkswagen are the same. I have owned a $60K 2008 BMW 535xit (tourning - twin turbo) and it was constantly in the shop (new turbos at 50K, new front suspension bushings, leaking drive train, numerous fuel injection problems and defective fuel pumps, broken electric water pumps, and the list goes on... I got rid of it when I hit 60K since I knew from past experience reaching 100K would be extremely expensive. Completely unacceptable. Our 2010 Mercedes C300 had a balance shaft defect in the engine, broken interior door handles - requiring a complete replacement of the door trim? Defective wheel bearings, defective locks, again all these problems right after the manufactures warranty expired (50K)! I have had nearly 10K of repair bills. I also got rid of the car. These are not isolated cases, they are well documented problems with the cars I have mentioned above prompting several class action lawsuits (against BMW in particular) for defective engineering leading to potentially dangerous situations caused by such poor quality. Reliability = quality. It is rather amazing that people tend to ignore these issues and continue to buy these cars just because they are the shinny pretty penny on the outside that feeds a certain status symbol. I also have a 13 year old Lexus that has over 200K miles on it going strong...
German brands have ranked among the worst reliable cars on market with the most problems per cars sold (Consumer reports, JD Power, etc.). There is simply no excuse for these types of failures and repairs on such expensive cars. A friend of mine has a 2012 BMW 550 V8 and between the constant fuel injection issues and large amounts of oil consumption his car is always in the shop (All documented problems).
We have a saying on this side of the Atlantic - you lease German cars and buy Japanese! In fact the German manufactures know this and are constantly providing incredibly low lease deals to move their cars (along with free maintenance), the deals are sometimes too good to pass up.
While it seems that I am bashing German cars, that was not my intent. I just want to point that that before you make a generalized statement think about what you are saying. In my opinion, French cars are no worse or no better than any other European brand, they just don't happen to be as shinny and pretty on the outside as some of their rivals, former reputations and good looks can be deceiving.