In 1789, he was returned as one of the deputies of the Third Estate in Paris to the Estates-General, and he was instrumental in writing up the cahiers de doléances of Paris. He went on to support revolutionary measures such as the union of the orders, the suspensive veto, the Civil Constitution of the Clergy, the last of which he was one of the principal authors. He was one of many deputies named to the Constitutional Committee in September 1789, to replace those conservative members who resigned.