It's Paris in the late Forties. A young man (Robert Hutton), with his wife (Patricia Roc) and his girl friend (Jean Wallace), is overheard in a bar bemoaning how long it will most likely take before his rich aunt dies and he will inherit a great deal of money. A few days later the aunt is stabbed to death.
You can stream The Man on the Eiffel Tower (1950) free and legally on OldReel, via the Internet Archive.
Yes — it is in the public domain and can be watched and shared freely.