ASCAP says YOU WILL FIND YOUR LOVE IN PARIS was written by Mack Gordon, Guy Lafarge, and Flavien Monod. It also gives LA SEINE and RIVER SEINE as alternate titles. (Maybe Flavien Monod was author of the French lyrics?)

The Internet Movie Database (IMDb) says LA SEINE was used in the 2002 film "The Quiet American." (It doesn't appear in the soundtrack album, though.) It gives this description:

"La Seine"
Composed by Guy Lafarge / Flavien Monod
(c) 1948 Société des Editions Royalty (assigned to Editions et
Productions Théatrales Chappell)
Used by permission of Warner / Chappell Music Australia Pty Ltd.
All rights reserved
Performed by Christian Dollslager

The Online 78 rpm Discographical Project says THE RIVER SEINE was recorded by –
Alex Alstone, on MGM 30580, around 1946 to 1952.
David Rose and His Orchestra with vocalist Beryl Davis, on MGM 30830. On that recording, "Lafarge-Roberts-Holt" are credited as songwriters.
Guy Lombardo and His Orchestra, on Decca 28925, in 1949.
Guy Lombardo and His Orchestra, on Decca 24765, in 1949.