West of Paris (north of Paris is very halal too, but there's a majority muslim population there).
Quick burger that recently got attacked in several locations in France for selling only halal burgers without telling the local population that it had changed meat supplies (at first). They now provide non-halal burgers in those locations, "produced elsewhere and wrapped in cellophane."
http://www.dw-world.de/dw/article/0,,6016381,00.html