The best part of the movie is the opening credits. The music is wonderful, and the animation a hoot. I wish that energy and fun carried through the whole movie.
Sellers works like he's broke and the rent is due tomorrow in this movie. The script has to be really weak to make Niven and Wagner look meh.
Watch this for mind candy entertainment. The scenery is beautiful. The tiny foreign cars. The women all decked out in Yves St Laurent. Sellers being Sellers.
It's not a bad film, just awful script and not so hot directing. Nivea had the lead role, but you'd never know it here.
Read the NYT 1964 review. Crowther more eloquently wrote what I thought.