France's far-right figurehead Jean-Marie Le Pen has been taken to hospital suffering from "general fatigue", his lawyer said Wednesday.

The increasingly frail 89-year-old was set to face a verdict on Wednesday in a hate-speech case over comments he made about homosexuals.

Explaining his absence in court, his lawyer Frederic Joachim produced a hospital certificate saying he had been admitted "in an emergency, for an undetermined time".

Le Pen co-founded France's National Front (FN) party in 1972 and built it up into a formidable national political force known for its virulently anti-immigration and anti-EU policies.

His daughter Marine took over in 2011 and has since distanced herself from his controversial legacy which included a string of xenophobic and anti-Semitic comments that led to convictions.

She kicked him out of the FN in 2015 and changed the name of the party -- against his wishes -- to National Rally at the beginning of the month.

Jean-Marie was hospitalised for about a week in April because of flu and a "dangerous pulmonary complication", his aide Lorrain de Saint Affrique told AFP.

He also spent several days in hospital in April 2015 with a heart problem, linked by party sources to stress from the highly publicised political blow-up with his daughter.

Le Pen's latest hate speech case was adjourned in his absence until October 3.

He is being prosecuted on charges of inciting hatred and violence after comments that conflated homosexuality and paedophilia and suggested that gay couples should keep out of the public eye.

Those remarks in 2015-2016 fit his life-long habit of causing offence, most notoriously when called the Nazi gas chambers a "detail" of history.

He also infamously claimed that the Nazi occupation of the northern half of France was "not particularly inhumane" and that the Ebola epidemic that swept West Africa in 2014 could help "solve" Europe's "immigration problem".

Despite his advancing years, Le Pen keeps up his regular media appearances and is still a lawmaker in the European parliament.

But as well as the rebranding of his beloved National Front, he was hit last month by news that his favourite grand-daughter had decided to jettison the family name.

Marion Marechal-Le Pen, a 28-year-old MP until June last year, has announced that she will now be known simply as Marion Marechal.

"Marion perhaps thinks that it is too much weight to carry," Le Pen lamented.

He also recently cancelled his attendance at a party on a riverboat in Paris, which was organised by a friend to mark his 90th birthday on June 20.

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