Dédoublonnage

Option Explicit

Sub Del_Doublonsc()
Dim X As Integer

Application.ScreenUpdating = 0

For X = Range("C65536").End(xlUp).Row To 1 Step -1
        If Application.CountIf(Range(Cells(X, 1), "A1"), Cells(X, 1)) > 1 Then
                Rows(X).Delete
        End If
Next X
End Sub

Option Explicit

Sub Del_Doublons()
Dim X As Integer

Application.ScreenUpdating = 0

For X = Range("C65536").End(xlUp).Row To 1 Step -1
        If Application.CountIf(Range(Cells(X, 3), "C5"), Cells(X, 3)) > 1 Then Rows(X).Delete
Next X
End Sub