Sub Test2()
origine1 = ActiveSheet.Name
origine2 = ThisWorkbook.Name
'Cells(1, 1).FormulaR1C1 = "=SUMIFS(C[1],C[2],RC[3])"
'Cells(1, 1).FormulaR1C1 = "=SUMIFS([Classeur1]Feuil1!C2,[Classeur1]Feuil1!C1,RC[3])"
Cells(1, 1).FormulaR1C1 = "=SUMIFS([" & origine2 & "]" & origine1 & "!C2,[" & origine2 & "]" & origine1 & "!C1,RC[3])"
End Sub