Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim r As Range
Set r = Intersect(Range("c6:C" & Rows.Count), UsedRange)
If r Is Nothing Then Exit Sub
For Each r In r
If r <> "" And Not IsNumeric(CStr(r(1, 2))) Then
Application.EnableEvents = False 'désactive les évènements
r(1, 2).Select
Application.EnableEvents = True 'réactive les évènements
MsgBox "Entrez le montant en " & ActiveCell.Address(0, 0)
Exit For
End If
Next
End Sub