According to L'Equipe, the 23-year-old has said yes to a move to the City Ground this summer and the two clubs have now agreed to a £26 million deal.
Kalimuendo has just two years remaining on his contract at Rennes and was expected to leave following an impressive 2024-25 by the French Club.
The striker was a rare bright spark for Rennes as they stumbled to a 12th placed Ligue 1 finish, scoring 17 goals and providing three assists in his 33 league games.
Forest continue to bolster their attack following the departure of Anthony Elanga, with Dan Ndoye already signed and Morgan Gibbs-White signing a new deal.
