According to the book תוספות הר"ש משאנץ כתובות - Tosfot of the RaSh of Sens Ketubot, which is a printing of the Cambridge 508.1 MS1 by Avraham Lis, the author of this tosfot is the RaSh of Sens.
1 I haven't managed to access the manuscript itself online. For a little more info on the MSmanuscript, see here.