This is an extremely uneven entry from the Gendarmes series, featuring Michel Galabru at a definitive peak (for the series) but De Funès alternating between brilliance and actual boredom (like what his character goes through at first in the film). Maybe this weariness my wife and I detected in his performance here was a foreboding of some of his health issues which will, a few years later, make him stop shooting physical comedy altogether, and will finally take his life so prematurely.
His faithful partner Claude Gensac wrote in her autobiography that De Funès' humour was a logical one. His characters were behaving logically even in their over-the-top reactions. But here when he goes nuts over being pampered and looked after all the time by his rich wife's staff, he insists upon dirtying the car on purpose in order to have a chance to wash it by himself and thus splashes paint all over it
only to empty in the process another bucket of paint on top of his own head
You would never have seen a gag like this in a classic Gendarmes such as "Le gendarme de St. Tropez" or "Le gendarme se marie", because it does not make sense! That the priest enters into a grimace contest with De Funès in plain view before his wife – however funny some of those face exchanges can be – doesn't make any sense either and is gratuitous! There is also mediocre acting on the part, for instance, of the butler, which doesn't help some of those poorly written, ill-warranted or directed scenes
But when the Gendarmes don their uniforms under the orders of the hilariously perfect (i.e. constantly serious, grave and solemn) adjutant Gerber, we are OK gain, and the situations can get really funny, like the talking whistle bit which another reviewer has described so well!