Dinner at the Ritz was done while David Niven was making his first visit back to the old country. Sam Goldwyn who made as much money with Niven by selling his services to major studios as using Niven himself, lent him out to 20th Century Fox for this European production.
The chief recommendation for Dinner at the Ritz is the location shooting in Paris, Monte Carlo, and London. It was good for American audiences to see the real deal as opposed to studio set recreations. It wasn't bad for our audiences to see the beautiful Annabella who would be marrying Niven pal Tyrone Power shortly.
Annabella is the daughter of a banker who allegedly commits suicide after telling her he was going to confront one of a group of six men who pulled off a swindle on his bank. Of course Annabella doesn't believe it, neither does detective David Niven who's after these guys for other crimes.
Since we already know who the murderer is, there's no real suspense in Dinner at the Ritz. It's whether she can catch them and prove it and will she realize Niven ain't one of the gang.
I will say this, the gimmick used to get her father's money back is pulled off with quite a bit of style.
Look for some good performances by Francis L. Sullivan and Paul Lukas as two of the gang of six. But the film really could have used some Hitchcock touches.