In France , buying, selling and carrying fakes is illegal.
At the airports, the Customs Officers are very strict.
If they find something suspicious on you or in your luggage, they look at the item very carefully.
They are trained. They look at everything, tags... Finishings especially.
I once had a problem with a Christian Dior T shirt which was in my luggage.
The lady officer looked at it very carefully. It was authentic and she then acknowledged it.
Had it been a counterfeit, I would have been fined twice the price of the authentic item.
The T shirt would have been confiscated and later destroyed.
A friend of mine was even sent to court for importing a fake Chanel watch.
In the street, the "flying "Customs Officers can stop you.
But... I have never heard of anyone being.... stopped!
In the airports we have posters:
Fausse Cartier, vrai casier= fake Cartier real police record
A real lady doesńt buy counterfeits!