The Front National founder, who was expelled from the party over anti-Semitic remarks, took aim at an emotional eulogy delivered by Xavier Jugelé’s husband as his daughter battles for the French presidency.
The 88-year-old’s latest remarks came as Marine Le Pen was engulfed in yet another scandal, which has seen her replacement as party leader stepping down amid accusations of holocaust denial.
Mr Le Pen said in a video posted on his website that he was “astonished” by the speech watched by Francois Hollande and hundreds of gathered dignitaries, police officers and members of the public.
“It seemed to me that there was something dubious about this ceremony,” he said.
The husband of the policeman who was murdered last week in Paris delivers an emotional eulogy at his memorial service pic.twitter.com/yGfVNQ1IXZ— Channel 4 News (@Channel4News) April 25, 2017
“The long speech he made in some way institutionalised gay marriage, exalted it publicly, and that shocked me a bit.
“I think this domestic peculiarity should be kept away from this kind of ceremony, which itself would gain more discretion.”
Etienne Cardiles described how he left his husband sleeping to go to work on what seemed like a normal day on 20 April.
They discussed their holiday plans throughout the day, before Mr Jugelé fell silent amid news of a shooting in Paris.
He was shot dead on the Champs Elysees after a man armed with a Kalashnikov opened fire on his police van in an attack claimed by Isis.
Mr Jugelé had also been among the officers deployed to the Bataclan during the group’s November 2015 attacks, returning to the concert hall for its reopening to “celebrate life”.
“When the first messages were issued that a serious incident was taking place on the Champs-Élysées, and that a policeman had lost his life, a little voice inside told me that it was you,” Mr Cardiles said.
“I returned home that evening without you, with an extreme and profound pain that maybe one day will weaken, I don’t know.”
Addressing his husband’s killer, suspected Isis supporter Karim Cheurfi, he added: “You will not have my hatred.
“I do not feel it because it is not like you, Xavier. Because it doesn’t correspond with anything that made your heart beat, nor what made you a police officer.
“A life of joy and smiles in which love and tolerance were your uncontested masters. You lived like a star, you leave like a star.”
The legalisation of gay marriage in France was one of the flagship policies of outgoing President Francois Hollande’s five years in office, a move that was popular with many people in France but controversial with a large conservative section of society.
Mr Le Pen was an outspoken opponent of the law, being quoted as describing homosexuality as “a biological and social anomaly”.
Following a lengthy public spat with his daughter, he was expelled from the Front National in 2015 for describing Nazi gas chambers as a “detail” of history.
Meanwhile, Ms Le Pen is languishing in opinion polls ahead of the decisive vote against centrist candidate Emmanuel Macron, after years of attempting to gain popular support by cleansing the Front National’s anti-Semitic and xenophobic image.
She temporarily stood down as party leader this week, claiming the move allowed her to concentrate on a presidential campaign “above party politics”, but they have continued to damage her chances.
Her expected replacement in the Front National, vice president Jean-Francois Jalkh, abruptly resigned over allegations – which he strongly denies – that he was a Holocaust denier.
Ms Le Pen’s partner Louis Aliot said the politician would take legal action over the claims and “wants to defend himself”.
Steeve Briois, another of the party’s four vice presidents, is taking Mr Jalkh’s place after allegations emerged over a conversation with a researcher in 2005.
He is said to have described the work of Holocaust denier Robert Faurisson, who was previously convicted for “complicity in contesting the existence of crimes against humanity”, as “serious” and “rigorous”.
In the run-up to her bid for power, Ms Le Pen has sought to recast the Front National as a nativist, or “French first” party that opposes immigration, globalisation and the EU.
As she and her party grappled with the latest potentially damaging turn of events, Mr Macron made a campaign visit to a village commemorating the massacre of more than 600 men, women and children by Nazi soldiers in 1944.