The 23-year-old midfielder moves to Vicarage Road from Ligue 1 side Rennes for a reported fee of £8 million.
"The opportunity to sign Abdoulaye Doucouré now was one we wanted to act upon, given our long-standing interest in the player," CEO Scott Duxbury told the club's website.
Championship
Watford cancel Qatar friendly after supporter backlash
27/06/2022 AT 12:37
Doucoure made his debut for the Ligue 1 club in 2012 having come through their youth system.
The France U21 international has signed a four-and-a-half year deal with the Hornets but will go on a six-month loan to Granada CF, who are also owned by the Pozzo family.
Watford have also signed 18-year-old forward Adalberto Penaranda from Udinese, another Pozzo club. He was on loan to Granada, and will stay on loan at the Pozzo-owned Spanish club until the end of the season when he will link up with Watford.
Premier League
Everton miss chance to pull away from bottom three after dreary Watford draw
11/05/2022 AT 18:00
Premier League
Watford down after Palace loss, Burnley slump to Villa defeat
07/05/2022 AT 16:38