Jean-Clair Todibo has completed his medical at West Ham ahead of a move to the Premier League club.
The 24-year-old played a key role in Nice securing Europa League football with a fifth-placed finish in Ligue 1 last season and made 33 appearances in all competitions.
West Ham technical director Tim Steidten travelled to France in a bid to secure the former Barcelona star's signature with the club determined to shore up their defence ahead of Kurt Zouma's imminent departure.
With the club captain set to depart, Julen Lopetegui has set his sights on bolstering his defensive options for the coming campaign.
Sky Sports reported Todibo has completed his medical in east London with an official announcement due shortly.
The agreement is set to see the Frenchman initially join Lopetegui's side on a season-long loan, with a £34million mandatory purchase agreed for next summer.
After graduating from the Toulouse academy, the centre-back made his senior debut for the club's first-team in 2018 before joining Barcelona on a free transfer the following year.
Todibo would make just five appearances for the Catalan club and would be shipped off on loan to both Schalke and Benfica before joining Nice in 2020.
The 24-year-old has made two appearances for Les Blues after being handed his senior debut last year
After initially arriving at Les Aiglons on loan, the move was made permanent in June 2021.
Since then Todibo has established himself as one of Europe's most promising defenders and was duly rewarded for his performances at the Allianz Riviera with a senior France debut in September.