When the gendarmes discover the small alien device that indicates that 2 of them are in the restaurant, Taupin says that the device fell from the purse of one of the girls on the beach. If Taupin refers to some of the 3 girls in the blue bikini on the beach scene, none of them were carrying any purses.
When Cruchot attacks the Colonel at the Gendarmerie gate. The interior behind the door (the set) is completely different from the real interior of the gendarmerie, seen from the outside.
The shadow of the camera operators it's seen on the gendarmes' back in two shots during the final fight.
Adjudant Gerber calls his wife 'Germaine' (instead of Cecilia) and she calls him 'Antoine' (instead of Jérôme)