Torch begins its journey at English home of Paralympic Games
British Paralympic athletes Gregor Ewan and Helen Raynsford battled pouring rain to light the flame.
"It has been such an honour to be able to take part in this," said Raynsford, the first Paralympic champion in para-rowing when the sport debuted in Beijing in 2008.
Ewan has competed in wheelchair curling three times at the Winter Games.
The Paralympic movement dates back to 1948, when German neurologist Ludwig Guttmann organised sporting events for injured war veterans at Stoke Mandeville Hospital, northwest of London.
"He created a sporting and social movement that today has a profound impact globally, advancing the lives of millions of persons with disabilities," said Andrew Parsons, International Paralympic Committee president.
The flame was lit in a stadium not far from the hospital where Guttman worked.
This is the first time since 2012 and the London Games that the Paralympic flame has been lit in Stoke Mandeville.
"Behind this flame is a powerful message of peace... and other strong values," said Tony Estanguet, president of the Paris 2024 organising committee for the Olympic and Paralympic Games, hailing Guttman's "vision".
Downpour
The three-time Olympic canoeing champion joked that the "capricious" weather was still "with us", a month after the opening ceremony of the Paris games was hit by a similar deluge.
The Stoke Mandeville Games were held to coincide with the 1948 London Olympics on grounds next to the hospital, which were then developed into the stadium where Saturday's ceremony took place.
The first Paralympic Games took place in Rome in 1960, with 400 athletes competing from 23 countries.
The flame will pass through the Channel Tunnel on Sunday, with 24 British torchbearers taking it halfway, before handing it over to 24 French torchbearers, who will take it to Calais.
Then 12 torches will travel across France from Sunday to Wednesday. The flame will then reach Paris and the Olympic cauldron, located in the Tuileries Gardens.
A thousand torchbearers will take turns in around 50 cities.
The main flame coming from Stoke Mandeville will pass through Calais, Arras, Amiens, Louviers and Chambly before arriving in the Paris region.
The Paralympic Games will begin on August 28 with an opening ceremony between the Champs-Elysees and the Place de la Concorde orchestrated, like those that signalled the start of the Olympic Games in July, by artistic director Thomas Jolly.
Some 2.5 million tickets have been put on sale for the event. As of Wednesday, just over 1.75 million had gone with around a dozen sports almost sold out, according to organisers.
Around 4,400 athletes will compete in 549 events, which will take place in 18 competition sites, including 16 identical to their Olympic counterparts.
These include the Grand Palais, the Chateau de Versailles and the Stade de France.