Bonsoir
Essayes comme cela
Private Sub ComboBox1_Change()
'Textebox agent copier
Dim Copieragent As String, Colleragent As String, Copiergrp As String, Collergrp As String
Copieragent = Application.WorksheetFunction.VLookup(ComboBox1, Sheets("Données3").Range("tabloagent"), 2, False)
Colleragent = Application.WorksheetFunction.VLookup(ComboBox1, Sheets("Données3").Range("tabloagent"), 3, False)
TextBox1.Value = Copieragent
TextBox2.Value = Colleragent
End Sub