Private Sub Worksheet_Change(ByVal Target As Range)
Dim c1 As Range, c2 As Range, c3 As Range
Set c1 = [A1]: Set c2 = [A2]: Set c3 = [A3]
If Intersect(Target, Union(c1, c2)) Is Nothing Then Exit Sub
c3 = c2
If c1 = "" Then Exit Sub
With c3.Characters(InStr(c3, c1), Len(c1)).Font
.ColorIndex = 3 'rouge
.Bold = True 'gras
.Size = 20
End With
End Sub