Sub Macro3()
Dim Bloc As Shape
Dim i As Integer
With ActiveSheet.Shapes("Bloc").TextFrame
If Len(ActiveCell.Text) <= 255 Then
.Characters.Text = ActiveCell.Text
Else
.Characters.Text = ""
For i = 0 To Int(Len(ActiveCell.Text) / 255)
.Characters(.Characters.Count + 1).Insert Mid(ActiveCell.Text, (i * 255) + 1, 255)
Next
End If
End With
End Sub