A few years ago I was parked up at Citie De Europe whilst wife did the last minute shopping, suddenly a van and a car full of gendarmes arrived and started looking at all the british registered vehicles on the car park, they then started to issue tickets to all of them that did not display a nationality plate on the rear or did not have beam deflectors on the headlights, the guy parked next to me protested that he had only just come over on the shuttle and would be going back in the afternoon, both trips in broad daylight, no such luck ! he still got an on the spot fine.
This was the first and only time I have seen this happen but it made me realise that for the sake of a couple of pounds and 3 minutes time to fit them its far better than a €50 fine.
Regards Phil