To find out Julia and Hadley met in Paris in the late 1940's - makes me happy. Two wonderful exciting lives that I have read about.. colliding.. simply incredible. Paul, Julia's husband first met Hadley (when she was still married to Ernest Hemingway) in the 1920's. Once the Child's were living in Paris they attended Hadley's Thanksgiving feast with her new husband Paul Mowrer. The two couples became very close, so close that when Hadley (and Hem's) son Jack Hemingway was to marry in 1949 - Julia wanted to throw the newlyweds a party! Moreover, 'the Mowrer's asked Julia to be the Matron of Honor because she was the only friend they had in Paris who was taller than the bride' haha. Of course Gertrude Stein attended Julia and Paul's party, being that she is the Godparent of Jack Hemingway.
Jack with Gertrude in Paris, 1924
Info and image from Julia's Cats: Julia Child's Life in the Company of Cats By Patricia Barey and My Life in France By Julia Child, wikipedia