Celtic have been linked with a move for £7million-rated Christopher Jullien.
The centre-back is currently playing his trade with Toulouse in Ligue 1.
According to French newspaper L'Equipe the 26-year-old has already travelled to Glasgow and been shown around both Celtic Park and the club's Lennoxtown training centre.
Jullien has played nearly 100 top-flight games in France, having had previous spells with Auxerre and Dijon, while he also counts Freiburg among his former clubs.
Standing at 6ft4in he is dominant in the air, featuring in the top 10 for aerial duels contested and success rate during the 2018/2019 Ligue 1 campaign.
He is seen as a replacement for Dedrycj Boyata and Filip Benkovic who joined Hertha Berlin and returned to Leicester City respectively.
Meanwhile, on Wednesday evening Celtic agreed a fee with Motherwell for the transfer of David Turnbull.