Celtic will need to offer French club Toulouse a fee of between €8m and €10m to complete the signing of centre-back Christopher Jullien.
The Scottish champions have pinpointed the 26-year-old as someone they want to bolster their defensive options and are keen to take him to Celtic Park.
Jullien was recently hosted by Celtic and shown around the club's facilities, as the Scottish side attempted to sell a switch to the club to the defender.
However, if Celtic want to sign Jullien then they will need to splash the cash as, according to French sports daily L'Equipe, an asking price of between €8m and €10m has been set by Toulouse.
Jullien, who has made 99 appearances in Ligue 1 for Toulouse, had not made a decision on his future and it remains to be seen if his trip to Scotland has swayed him towards Celtic.
Jullien came through the youth ranks at Auxerre before then being snapped up by German club Freiburg.
Toulouse brought the former France Under-20 international back to his homeland in 2016 and he is under contract at Les Violets until the summer of 2021.
Jullien helped Toulouse to avoid relegation from Ligue 1 this season, as his side finished 16th.
