File Photo: Former Liverpool s Midfielder Takumi Minamino. AFP
The 27-year-old Japan international scored 14 goals in 55 games overall for Liverpool after joining from Red Bull Salzburg.
Although he won three trophies at Liverpool _ including the Premier League title in 2020 and both domestic cups last season - Minamino struggled to break into Jurgen Klopp's star-studded side.
Monaco gave no financial details but reports estimated the transfer fee at 15 million euros ($15.8 million).
Minamino is the second attacking player to leave the Champions League runner-up after Senegal forward Sadio Mane joined Bayern Munich last week.
Coach Philippe Clement's attack-minded Monaco finished third last season to reach the qualifying rounds of the Champions League.
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