To add to Trev’s excellent information. Christofle acquired Cardeilhac, a very prestigious maker, in 1951, and kept their trademarks, as you can see on your flatware. You’re quite right, Christofle was largely a silverplate maker, but for decades they’d subcontracted to Cardeilhac when they wanted to produce 950 silver, so the relationship between the two firms had been ongoing. Thus your service dates no earlier than 1951. The pattern was by Cardeilhac, produced by Christofle.
As a side note, your service has been used and abused. I hope a bit of TLC can restore it.