In May 2001 he was appointed Minister of Mines, Energy and Hydraulics, serving until April 2006, when Yayi Boni became President.
Fassassi was elected to the National Assembly as a candidate of the Union for Future Benin in the March 2003 parliamentary election.
In the election, which Boni won, Fassassi took ninth place with 0.98% of the vote.
He died on December 4, 2016 at CNHU (national university hospital center).