Apologies for late response...Had an urgent matter to attend to...Yes, solved here too...
Sub TRANSFERT()
Dim WsP As Worksheet, WsM As Worksheet, debut As Date, fin As Date
Set WsP = Sheets("PARAMS"): Set WsM = Sheets("MARKETS")
debut = WsP.Range("F11").Value
Set trouver1 = WsM.[R:R].Find(debut, , xlFormulas, xlWhole)
If Not trouver1 Is Nothing Then adresse1 = trouver1.Row
fin = WsP.Range("K11").Value
Set trouver2 = WsM.[R:R].Find(fin, , xlFormulas, xlWhole)
If Not trouver2 Is Nothing Then adresse2 = trouver2.Row
End Sub