why did charles darnay decide to go to Paris

Darnay claims to know the man and promises to deliver the letter to him. He opens it, and it is a plea for help from Monsieur Gabelle, who has been imprisoned after all. Darnay feels responsible because Gabelle has been arrested for the upkeep of the Marquis’ property. Darnay feels justified in having renounced his title, but he worries that he did not settle affairs in the manner that he should have, and he resolves to go to Paris. He assumes that his gesture of handing over his title will make him welcomed by the revolutionaries.