According to reports, Strasbourg are looking for £25m to sell Diarra in the summer. Not only Forest, but Aston Villa are also interested in signing the young midfielder.
Strasbourg had previously rejected a £15m offer from Eintracht Frankfurt for Diarra's services.
Nottingham Forest have a connection to Diarra through Andrew Omobamidele, who is currently on loan at Strasbourg with a permanent option. This might give Forest an advantage in their pursuit of Diarra.
Diarra is a versatile player who can play both in midfield and as a winger.