Bonjour,
A tester.
Cdlt.
Option Explicit
Private Sub Worksheet_Activate()
Dim ws As Worksheet, ws2 As Worksheet
Dim rng As Range
Dim dt As Date, lCol As Long, lRow As Long
Dim n
Set ws = Worksheets("Données")
Set ws2 = Worksheets("Source")
dt = ws.Cells(1, 2).Value
With ws2
lCol = .Cells(1, .Columns.Count).End(xlToLeft).Column
lRow = .Cells(.Rows.Count, 1).End(xlUp).Row
Set rng = .Cells(1).Resize(lRow, lCol)
End With
On Error Resume Next
n = Application.Match(CLng(dt), rng.Rows(1), 0)
If Not IsError(n) Then
Me.Cells(1).Resize(rng.Rows.Count).Value = rng.Columns(n).Value
End If
End Sub