"Fats" Sadi Pol Lallemand (23 October 1927, Andenne, Belgium – 20 February 2009, Huy) was a Belgian jazz musician, vocalist, and composer who played vibraphone and percussion. He chose the name "Sadi" because he disliked his last name, which means "the German" in French. He had his own quartet and nonet. Sadi won the Belgian Golden Django for best French-speaking artist in 1996.
After World War II, he became a professional vibraphonist. He performed with Jacques Pelzer in the Bob Shots, then with Django Reinhardt, Kenny Clarke, Stéphane Grappelli, and Don Byas when he was in Paris (from 1950 to 1961), also co-leading a quartet with pianist Martial Solal in 1955, which recorded the following year. He was a member of The Kenny Clarke-Francy Boland Big Band. On his return to Belgium, he worked for RTBF, the TV channel of the French Community in Belgium. Sadi became seriously ill in January 1995 and appeared rarely on stage.