When his wife died in 1789 he married a rich widow, Anna Maria Kirsberger, with whom in 1793 he had a further son, the novelist Charles Paul de Kock.
Still upholding his republican ideals he founded the "Comité Révolutionnaire Batave" which formed and sent to the Dutch Republic a force of volunteers under General Daendels.
When the French Revolution began in 1792 de Kock expressed his backing for the planned assassination of King Louis.
In March 1794, having by now left the bank, he was accused by the Committee of Public Safety (the provisional government in France during the Reign of Terror), of being a agent for the British.
He was arrested at his home on March 18 and taken to the Conciergerie where the public prosecutor Fouquier-Tinville charged him with having had meetings against the government and of having been the friend of the traitor Dumouriez.