Sub test()
Dim groupe
Set groupe = CreateObject("scripting.dictionary")
For i = 1 To Cells(Rows.Count, 1).End(xlUp).Row
groupe(Cells(i, 1).Interior.Color) = groupe(Cells(i, 1).Interior.Color) & Cells(i, 1).Address(0, 0) & IIf(i < Cells(Rows.Count, 1).End(xlUp).Row - 1, ",", "")
Next
For Each elem In groupe
MsgBox "pour la couleur " & elem & " c'est la plage " & groupe(elem)
Next
End Sub