Yves Montand was a prominent French actor and singer, a crooner who was discovered by Edith Piaf and had a long, exemplary career. He was not well known in North America... Although perhaps he should have been.
And, according to various sources, including the famed Encyclopedia Britannica, Montand was born in Italy as Ivo Livi, Jew.
Sadly, that does not seem to be entirely true. Yes, Montand was originally an Italian named Ivo Livi, and it is this pseudo-Jewish last name that led to the claims. In fact, during World War II, the Nazis thought that Montand was Jewish, thinking that he changed it from Levi to Livi... He explained that if he did change it, it would have been a little less obvious (which he would... later). Thankfully for Montand, the Nazis bought it.
So why should the non-Francophiles know of Montand? Well, he was partially responsible for breaking up the Marilyn Monroe - Arthur Miller marriage after having an affair with Marilyn on the set of a "Let's Make Love".
An exemplary career indeed.