Not so sure about that.
There's http://www.geni.com/people/Yehuda-ben-Yom-Tov-Treves-%D7%99%D7%94%D...
and his grandson
Yehudah ben Yitzhak (Sir Leon) of Paris
Judah ben Isaac, called Sir Leon of Paris, was one of the most illustrious French rabbis of the MiddleAges. He was born in 1166 and died in 1224. He was probably the grandson of Judah ben Yom-Ṭob of Paris, and a descendant of Rashi.
The grandson is Sir Leon?