My hassles in this department have been predominantly to do with "Customs PNR". It's my pet hate in aviation
If you think about it, PNR=PPR because only a fool is going to assume that an email/fax/AFTN message will
100% definitely be delivered to the policeman in the Customs office.
I was once refused a landing (from short final) by Padova (Italy) because they "apparently" did not receive any of the several faxes I sent them the day before. On another occassion, Zaragoza (Spain) summarily cancelled my departure flight plan for the same "apparent" reason (which I know for certain was false because I was standing next to the officer at Granada who phoned them with it).
In N Europe they tend to be more laid back but in the "olde job creation countries" they evidently are not...
AFTN messages (e.g. as sent with AFPEx) are no good for this purpose, presumably due to British Leyland type of job demarcation prevailing at airports i.e. the ATC/OPS person is not going to pass the message on to Customs.
So I generally don't fly to any Customs-PNR airport unless I have some sort of acknowledgement that they've got it.
G.A. is highly monitored in France
Yes, they have some sort of national radar service. This normally works very well, and makes for easy CAS transits in most cases. A flight plan is visible to all units along the route, whereas in the UK a VFR flight plan goes basically nowhere (visible) except the two ends.