Only relatives and close friends are expected to attend the celebration since a number of key Pheu Thai Party politicians are still prohibited from travelling by the National Council for Peace and Order (NCPO), the source said.
If they wish to leave the country, they must seek NCPO permission first.
The former premier chose to have the birthday party in Paris because he feared holding it anywhere near Thailand would be interpreted as a political move, the source said.
It remains unclear whether his younger sister and former premier Yingluck Shinawatra will attend the party.
Meanwhile, birthday celebrations usually held by Thaksin supporters at Wat Kaew Fa in Nonthaburi's Bang Kruai district will not be held this year.
The announcement was made on Friday by Singthong Buachum, a former Bangkok MP candidate for the Pheu Thai Party.
Talking about Thaksin's birthday party in Paris, former Democrat MP Watchara Phetthong said the former premier would likely use the event to send some kind of signal to his supporters.
He urged Thaksin to return and face punishment in Thailand.
He also called on the NCPO to ask French authorities to repatriate Thaksin.
Thaksin was ousted in the 2006 coup and and later fled the country to avoid a two-year jail term handed down for an abuse of power conviction stemming from an illegal land deal.
Last year, more than 100 MPs and ministers from Pheu Thai reportedly flew to Hong Kong to extend their birthday wishes to Thaksin.
He also broadcast a message to well-wishers who attended a merit-making ceremony to mark his birthday at Wat Kaew Fah.