The Catman of Paris is a decent thriller, typical of the 1940's. However, it's a total rip off of the far superior Cat People (1942) which was produced by Val Lewton and directed by Jacques Tourneur. [See the review elsewhere on my site.] That being said, Catman has a lot going for it. The cinematography is nice and the soundtrack is effective.
Furthermore, in spite of the predictable plot, the acting is solid through and through. Carl Esmond [Ministry of Fear] is very good as author Charles Regnier who has returned to Paris after publishing a controversial book. Early on in the film, he is the prime suspect in a series of murders that are being blamed on the "catman." The rest of the cast is solid as well.
I was hoping for a few more horror elements but they are not to be found. Most of the film has lots of cat shots for no apparent reason. Then, finally, when the Catman is revealed at the end of the movie, the makeup is tame at best. He hardly looks like the ferocious creatures that has been terrorizing all of Paris.
This Catman if Paris is a fine film but, by all means, watch Cat People instead. It's a perfect example of how to hit this kind of thriller way out of the ballpark even if you have a limited budget.
For more info check out the film's entry in IMDB.