Thank you Michael. Effectively, the colorspace of the timeline had a slight difference.
One output color space was on Rec.709 A et the other one on Rec.709 (Scene).
So I put them both on Rec.709 (Scene) but the problem remains.
I am looking at the file within DV on the same monitor, but on two different sequence and the grading still does not appear the same. Could vertical resolution (one is a 2160×3840) affect the color ?