Very odd, why is he even in Brum if we haven't agreed a fee?
If his French club put him up for sale at 10m Euros but have changed it to Sterling then we should immediately withdraw the offer completely and walk away.
No matter how good he is (or any player for that matter) once the selling club move the goal posts we should end all negotiations, that way any club dealing with us knows that if you try it on we will not proceed.