It was a mildly entertaining watch, filled with all of the sort of plot points / wacky goings on that you would expect from Sellers. There seems to be a lot of "forced" humour, in which the movie expects you to laugh but you really don't feel like doing so.
All-in-all, I would say it is worth a one time watch for Sellers' fans, but if like me, you see this and think of watching it, it's not really worth your time.
This is one of Peter Sellers' oddest films, and it's very patchy indeed. It's partly an Italian rip-off of "The Pink Panther" (complete with almost identical animated opening credits), only with Sellers as the wily master criminal instead of the cop. Though actually that's not quite true. The Fox appears to be a petty thief who repeatedly gets caught, and has absolutely no resources other than a gang consisting of three painfully untalented and desperately unfunny character actors who resemble the Three Stooges on elephant tranquilizers, so it's a bit puzzling why Interpol think he's the greatest criminal mastermind in Europe. And the theft of four tons of gold which occurs in the opening scenes and provides the basis of the entire plot is the work of some other guy we don't care about in the slightest, and everybody knows it. I suppose the ability to occasionally display flashes of semi-competence makes our hero a force to be reckoned with in a world where every cop has the IQ of mud.
The first half is simply a bog-standard farce in which everybody is exaggeratedly Italian, and the police can't catch a fugitive whose address they already know because they can't search a house properly or recognize him from more than three feet away if he's changed his clothes. Many jokes are prolonged well past their natural lifetime, and the prominence of those three guys who should never have made it onto celluloid as lobotomized foils for Sellers really, really doesn't help.
In the second half, it properly gets going. We meet the real star of this film, Victor Mature, parodying himself as a Hollywood beefcake legend desperately trying to act half the age he very obviously is. He's an absolute delight in every scene he's in, and this would have been a far better movie if we'd spent the first half seeing this insecure egomaniac's story unfold in parallel with that of the Fox, whose worthless trio of sub-moronic hangers-on who can't act mostly fade into the background once Sellers has Mature's character as a foil worthy of his talents. We also get a shift up in gear from Sellers, whose cunning plan to smuggle the gold into Italy is to pretend to be a director making a movie about that very thing. This is an excuse to mercilessly parody the pretentious excesses of certain Italian art-house film directors of the sixties, by implying very bluntly that a complete fake who had to desperately bluff his way through directing a movie would be indistinguishable from them. I suspect that making a movie with two target audiences, many members of both of which would have been bored and/or baffled by half of it, contributed to its commercial and critical failure.
Badly flawed - and there's something a bit odd about Britt Ekland being cast as Seller's sister who's supposed to be 16, seeing as she was his wife - though kind of interesting. And Victor Mature totally steals it. Incidentally, the director of the Old Testament epic we briefly glimpse is the actual director of this movie.