 Thành claimed to have arrived in Paris from London in 1917, but the French police only had documents recording his arrival in June 1919.In Paris he joined the "Groupe des Patriotes Annamites" (The Group of Vietnamese Patriots) that included Phan Chu Trinh, Phan Văn Trường, Nguyễn Thế Truyền and Nguyễn An Ninh.They had been publishing newspaper articles advocating for Vietnamese independence under the pseudonym Nguyễn Ái Quốc ("Nguyễn the Patriot") prior to Thành's arrival in Paris.