BRIDE OF THE SPOILER WARNING
Eau dear. There are a few film roles - a very few - that could never be played by any actor other than he or she who originated the role. You can get away with different actors as King Lear, James Bond or Hercule Poirot, since they're (at least nominally) from literary sources, but you can't really do it with characters created specifically for the films. An Indiana Jones movie with someone other than Harrison Ford as Indy simply isn't an Indiana Jones movie, just as a Saw film without Tobin Bell as Jigsaw is a Saw film in name only. Or a Pirates Of The Caribbean film in which Jack Sparrow doesn't show up. It's cheating. And a Pink Panther movie has to have not just Inspector Clouseau, but Peter Sellers playing him. It's the lerw. (Steve Martin, you deserve a slap.)
Son Of The Pink Panther is like something along the lines of Friday The 13th Part 5: the one which doesn't have Jason Voorhees in it but does have an entirely different character doing much the same things. In this instance it's Roberto Benigni as Jacques Clouseau's illegitimate son, similarly mangling his heavily accented English and causing havoc wherever he goes. Bafflingly, he's the son of Elke Sommer's character from A Shot In The Dark, except that she's played by Claudia Cardinale, who wasn't in that film but was in other Pink Panther movies as a different character. Herbert Lom is still Commissioner, of course, investigating the kidnapping of a North African princess as part of a needlessly complicated coup plot - a princess with whom Benigni has fallen in love.
There are a few laughs, sure. It's a Pink Panther movie made by Blake Edwards so it would be practically impossible for it to be completely laughless. We get the elaborate set-pieces, the face pulling, the physical routines, the wordplay. And Herbert Lom is magnificent. But it's not really a Pink Panther movie despite the many references to Clouseau - this man still isn't Clouseau no matter how many ludicrous disguises he employs, no matter how many times he rides his bicycle into the sea or says "bermp" instead of "bump". Strangely, the film has the look and feel of the two Bond films with Timothy Dalton - which is reinforced by having Robert Davi as one of the villains.
It's one of those movies that isn't completely terrible but isn't much good either: if you miss it you've not missed anything and it's not going to be retrospectively acclaimed as a lost classic in the year 2077. Its pleasures are entirely incidental - a Henry Mancini score (his last), some good comic business, but even those are scuppered by  having Bobby McFerrin doobedoo his way through a horribly vocalised opening theme and  staging one bit of comedy mayhem while a TV set shamelessly displays the Marx Brothers performing the same gags fifty years previously. It's better than Curse, obviously (what isn't?), but it's not up there with Return and certainly nowhere near the original. It's jerst not ferny enerf.
Go here to buy it, if you want: