JAR-OPS
Joint Aviation Requirements - Operations
From the JAA (Joint Aviation Authority) which is a (I hesitate to use this word) "governing" body which basically comes up with the European laws and requirements for commercial air travel based on ICAO with some improvements - as JAA is not an actual Government body these requirements actually have to be put into law by individual member states who may have their own laws as well (this should all change with the advent of EASA).
This basically means that although there is a standard set by JAR-OPS there may be some individual laws which are not common from country to country (like the French CC Diploma you have).
To overcome this airlines will require you to have the JAA minimum so that they are compliant with the law - in this case they are asking you to have undergone a Cabin Crew course at an airline "governed" by JAR-OPS - now I know the GCAA in the UAE likes to call itself JAA Compliant but as it is not an official JAA member you may have to do some digging to see if they will accept your current level of qualifications.
Sorry that was a rambling and long winded answer (hope it was right!)