He's not a "what".
Post of the Week Award!
I went looking for its artist. The Web Gallery of Art attributes it to an unknown French artist, but it looked Flemish to me - another source attributes it to 'Andrieu d'Ippre, peintre de Paris' who left Amiens for Paris in 1444, and died in Mons in 1450. So arguably Netherlands rather than French.
I would love to know who the beheaded bishop is - St. Denis maybe? Which would militate for French. But the saint with the amazing fur trimmed hat, crystal ball, sword, and little terrier dog is REALLY who I'd like to identify.