I got it, it's the Archbishop of Urgell, a spanish town in catalognia. So him and Sarkozy are actually coprince of Andorra.
Seems Andorra was funded in 1278 and earned independance in 1793 because of the revolution.
Hmm an interesting POD would be a war between France and Spain because of the Bourbon legacy aroubd 1720 (both kings were Louis XIV grandsons). As the french king is also coprince of andorra, if he win maybe the three countries are united with andorra as capital ?