I have already written a post on FNAC if you are in the market for electronics in Paris. I had been taking the metro to FNAC until found this Darty store just down the block. Darty is the leader of specialized distribution of electronic products for the general public in France. Another of their slogans is to satisfy 100% of the customers. Darty France also provides a repair service guarantee, that if a product is broken in the first one or two years (depending on the product) Darty will fix it. The company has different operations across Europe, the original being in France and now in three other countries (in conjunction with KESA), Turkey, Italy, Switzerland and Spain.
They have at least 15 stores in Paris and many more across France.
I looked at the selection and I found the camera selection was at least equal to FNAC and the computer selection, including routers, hard drives, phones and cables is better.
They also sell a large selection of kitchen supplies which is interesting to me.
These guys sell just about everything, including appliances.
If you are looking for electronics in Paris or elsewhere in France, Darty is another good option besides FNAC.