 He won the Belgian Cup in 1993, only 19, having scored in the final against R. Charleroi SC, and also helped the side to two runner-up league places (1992–93 and 1994–95), each time bowing out to Anderlecht.Subsequently, Léonard moved to France where he played with AS Monaco FC, also having a brief stint with OGC Nice.Whilst at Monaco, he scored in the semifinal of the 1997–98 UEFA Champions League against Juventus, in a 4–6 aggregate loss, being the only Belgian player to score at this stage of the competition; in the previous round, he helped oust Manchester United on the away goals rule after a 1–1 draw at Old Trafford.