Born in
Versailles, France, to an
Algerian father and an
Italian mother, Lacen started his professional career with modest
Stade Lavallois and
ASOA Valence. For the
2005–06 season he moved to Spain, joining
Deportivo Alavés which would eventually be relegated; he made his
La Liga debut on 15 October 2005, in a 1–1 home draw against
Villarreal CF. After two
second division campaigns as an undisputed starter for the
Basques, Lacen moved to
Racing de Santander on 15 August 2008, on a three-year contract. He competed throughout
the campaign for first-choice status with
Peter Luccin, also newly signed. In
2009–10, as Racing finished in 16th position, Lacen became an automatic first-choice (Luccin returned to
Real Zaragoza from his loan). He scored three goals, including in a 3–2 home win over
Xerez CD on 13 December 2009. In late February 2011, with his link to the
Cantabrians expiring in June, Lacen signed a pre-contract with fellow top-level side
Getafe CF. The move was made official on 25 May, with the player agreeing to a four-year deal with the
Madrid outskirts club. Lacen scored his first goal with Getafe on 16 April 2012, netting the second in a 5–1 home defeat of
Sevilla FC. He was released from his contract on 31 January 2018 after appearing in 187 competitive matches and, three days later, joined
Málaga CF until 30 June. ==International career==