It seems inevitable that if you are allowed to fly above cloud in France that at some point a situation will arise where you need to break cloud in order to land
It's not inevitable at all, unless you allow your IMCR to lead you into situations that you have no business being in, if you can't legally use your IMCR at that time.
I'm with 421C on this. I've flown on top of clouds on a number of occasions, but never where I couldn't see a way back down.
You need to be able see a way back down. That might be the end of the overcast a few miles off tracks, or it might be holes of sufficient size within view. When your last hole is starting to leave view you have little choice but to turn towards it and use that way out. If you don't then you run the risk of being in a situation that you describe. I don't think many pilots who don't have instrument qualifications but do have VFR on top privlidges will continue on in such a situation.
If they did continue on, then their principal escape route has to be to return to an area of known good conditions, but of course that could have changed by the time that they return to it.
So if you decide to continue on top with no escape route other than "expecting better weather ahead" then you are letting your instrument skills lead you further than you would go without them. The trouble is your instrument skills can't legally be used in France, so of course you can expect to have your decisions questioned afterwards.
As Pace say, you are not likely to be questioned for using your skills to get out of the situation, but more likely to be questioned for how you got yourself into the situation in the first place.
Those talking about forecasts of Sct or Bkn at the destination have gotten too use to instrument flying! No VFR only pilot with any sense will fly over an overcast relying on a weather forecast for a way back down. We all know that they can't be relied on like that.
IO540 said many years ago on a different subject, but is relevant to this...."you must always make sure that you have a way out." Hopeing that the forecast at your destination will prove true isn't having a way out, but rather 'hoping for a way out'.
If your only way out is to use skills that you aren't legally entitled to exercise in that country, then of course you are leaving yourself open to question. If you take that risk then yes envitably you will eventually have to use that skill that you arn't legally entitled to use, but most sensible pilots without such a skill would never have gotten themselves into that situation in the first place.
So...no gray area as far as I'm concerned. 421C has it spot on.
dp