The seat and food will be the same in C on B744 to FRA and A343 to MUC. The front C cabin is nice on A343 and B744 if you can get a seat there. Layover at FRA is 2 hr 35 min and at MUC 1 hr 45 min. You'll arrive in NCE earlier (18:15) via FRA, but as I mentioned earlier MUC is a better airport for connections. However, since 2 hr 35 min at FRA is more than sufficient there really isn't much to choose between the two options. I would pick whichever schedule that's more convenient.