Marseille signed France international Loic Remy from Nice on a five-year deal on Thursday.
Remy passed a medical in the afternoon before signing his contract with the French defending champion.
''He's a young international with a great potential,'' Marseille coach Didier Deschamps said. ''He has the ability to play in every attacking position. I expect him to play well and score goals. His pace and power make him dangerous for defenses.''
The 23-year-old forward has scored 25 goals for Nice in the past two seasons.
''The Champions League tilted the balance,'' Remy said of his decision. ''That's something I was looking forward to.''
Remy also drew interest from Hoffenheim but, unlike Marseille, the German club did not qualify for this season's Champions League.
''Things went very fast from the moment the Marseille management came to Nice yesterday,'' Remy said.
Marseille reached an agreement in principle with Nice on Wednesday evening.
The addition of Remy comes as a relief for Marseille, whose attack has been weakened this summer by the departures of Fernando Morientes, Bakari Kone, Mamadou Samassa and Senegal forward Mamadou Niang, the top striker in the French league last season.
''I expect a complete change compared to what I've known in Nice,'' Remy said, ''in terms of fans' expectations and pressure.''
Nice finished 15th in the French league last season.
