Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Cells.FormatConditions.Delete 'RAZ
If Intersect(ActiveCell, UsedRange, UsedRange.Offset(3)) Is Nothing Then Exit Sub '3 premières lignes du UsedRange exclues
With Union(Intersect(UsedRange.Rows(1), ActiveCell.EntireColumn), Intersect(UsedRange.Columns(1), ActiveCell.EntireRow))
.FormatConditions.Add Type:=xlExpression, Formula1:=1
.FormatConditions(1).Interior.Color = RGB(255, 150, 255)
End With
End Sub