Born to a Maltese father and Italian mother in Sousse in Tunisia, in 1963 Fenech's family was repatriated in France, where they settled in Givors.

In December 2005, Fenech was a member of the Parliamentary Commission of Enquiry about the Outreau trial (a judicial incident with men and women being held for years in jail on unfounded suspicions), which had been called by President Jacques Chirac in order to help prevent a recurrence of this situation through alterations in France's legal system.

The same year, he was appointed by Prime Minister Jean-Pierre Raffarin a mission to study the ankle monitor to strengthen the fight against recidivism.

On his initiative was created in the French National Assembly a Parliamentary study group on the homelessness, of which he became president.

On 27 March 2008, the Constitutional Council canceled his reelection on the grounds of violation of campaign finance laws and made him ineligible for one year.

[3] In June 2012, he was again found guilty by the 17th chamber of the Parisian Court, for public slander against a Catholic association he had attacked as a "cult" in the annual report of the MIVILUDES.