Option Explicit
Sub TestCellule()
Dim Messages, TableCel
Dim N As Long
Dim Message As String
TableCel = Array("A12", "G10", "b5", "b7")
Messages = Array("Civilité", "Nom", "Prénom", "adresse")
For N = 0 To UBound(TableCel)
If Sheets(1).Range(TableCel(N)) = "" Then
Message = Message & Messages(N) & Chr(13)
End If
Next
If Message = "" Then Exit Sub
Message = "Vous devez saisir :" & Chr(13) & Message
MsgBox Message, vbInformation, "Champs incomplets"
End Sub