[1] He led the French troops at the Battle of Peking in August 1900 where a multinational force ended the siege of foreign legations during the Boxer Rebellion.

Henri-Nicolas Frey was born on 9 January 1847 in Bocognano in Corsica, son of Henri Frey (1808–1887) who was a gendarmerie officer, then justice of the peace in Valensole, knight of the Legion of Honor, 2nd class[2] and his mother being Jeanne Carréga (1814–1886).

He got married on 19 February 1894 in Asnières-sur-Seine with Julie Bertrand, divorced wife of Charles Apert.

He served in the Bureau of The Marine Infantry Troops and was rapporteur of the Technical Committee of the Colonies.

As a young colonel in command of the 2nd Marine Infantry Regiment, he led a mission for the French Sudan Campaign in 1885–1886.