Sub TEST()
Dim Derlg&, Col&, Lig&, Plage As Object, Lettre$
On Error Resume Next
Derlg = Cells.Find("*", , , , xlByRows, xlPrevious).Row
Set Plage = Range("A7:q" & Derlg)
Lig = Application.Match([c1], Plage.Columns(3).Rows, 0)
Col = Application.Match([g1], Plage.Rows(Lig), 0)
Lettre = Split(Columns(Col).Address(ColumnAbsolute:=False), ":")(1) ' facultatif
MsgBox "La date :" & Application.Index(Plage, Lig, Col) & " se trouve en " & vbLf & "Ligne: " & Lig + 6 & vbLf & "Colonne: " & Col & " (" & Lettre & ")", , "Information"
If Err Then MsgBox "Il n'y a pas cette date en ligne " & Lig + 6, , "Information"
End Sub