Massi served as a minister in the government of the Central African Republic during the 1990s and again from 2005 to 2008; he was also the President of the Democratic Forum for Modernity (FODEM) party from 1997 to 2008.
After the victory of Ange-Felix Patassé of the Movement for the Liberation of the Central African People (MLPC) in the August 1993 presidential election, Massi joined the government of Prime Minister Jean-Luc Mandaba as Minister of Energy and Mineral Resources in October 1993, remaining in this position until June 1996.
He served as a Deputy from Baboua in the National Assembly from 1998 until François Bozizé seized power from Patassé in March 2003.
[3][7] On April 21, Massi signed an agreement to support Bozizé in the second round of the election,[8] and after Bozizé's victory, Massi became Minister of State for Equipment, Transport and Civil Aviation in the government of Prime Minister Élie Doté, which was named on June 19, 2005.
[13] FODEM established a provisional political bureau on 22 May 2008 with Joseph Garba Ouangolé as president, and it expelled Massi from its ranks.
[17] The Central African Ministry of Defense formally denied killing Massi in a statement on 21 January and said that the government did not know where he was.