Michael Rosenberg, an influential businessman in the Outremont Hasidic community, filed the lawsuit. He claims he is the victim of anti-Semitism.
For more than six years, Lacerte has reported on the community in his controversial blog, detailing what he considers bylaw violations committed by his ultra-Orthodox Jewish neighbours.
Rosenberg told the courtroom that Lacerte's blog posts accuse him of offences ranging from illegal double parking to influence peddling with the likes of Tony Accurso, the Quebec contruction boss entangled in allegations of corruption, and Frank Zampino, the former city official charged with fraud, conspiracy and breach of trust.
Rosenberg admitted to double parking but said he is not involved in corruption and called the blog posts defamatory.
The trial is expected to last four days.
In March 2011, A Quebec judge rejected a restraining order request against Lacerte.
Rosenberg sought the restraining order, claiming Lacerte harassed him and his family.
Lacerte's blog includes dozens of photos taken around an unmarked Hutchison Street synagogue founded by Rosenberg's family.