When he was transported back to Hanoi, he was held in Hỏa Lò Prison. At first, the French authorities did not release his real name, in order to avoid public disturbances, but it quickly leaked out who he was. A criminal trial followed, with all the charges going back to 1913 when he had been sentenced to death in absentia. The charges included incitement to murder and supplying an offensive weapon used to commit murder in two incidents, which had resulted in the deaths of a Vietnamese governor on 12 April 1913 and of two French majors on 28 April 1913. The court sentenced Phan to penal servitude for life. He was released from prison on 24 December 1925 by Governor General Alexandre Varenne, in response to widespread public protest. He was placed under house arrest in a house in Huế where Nguyễn Bá Trác lived. Trác was a former member of the Đông-Du movement who had become an active collaborator with the French. Guards kept the house under surveillance, so visits by his admirers were a bit inhibited. More public protests against his house arrest caused the authorities to allow him to move to a house which had been organised by his supporters. It was a thatched house divided into three sections and had a medium-sized garden. Here he was able to meet his supporters, his children and his grandchildren. In 1926, when Phan Chu Trinh died, Phan presided over a memorial service for him in Huế. In 1931, he also gave a speech at a rally celebrating the anniversary of the Yen Bai Uprising, during which Lý Tự Trọng shot and killed French secret police officials who might have been there to assassinate him. Phan spent his last fifteen years living a quiet life in Huế. He would often relax by taking boat trips on the Sông Hương (Perfume River). He died on 29 October 1940, about a month after Japan invaded northern Vietnam. Most cities in Vietnam have named major streets after him.