"Perhaps the spy should try writing poetry. It might help him overcome his aversion to many things." Jehan is not in the least hurt or offended by Javert's dismissal of his work. It's like music criticism from someone who has worn ear plugs.

"But his attempts at portraiture, perhaps, shouldn't be encouraged." Jehan leans over and reaches out, trying to grab the sketches. There's not much risk of harm in Javert showing Bossuet's likeness around Paris--but all the same, why permit any?