France's Bastille Day on July 14 faces scorching heat.
Heat warnings led to the dropping of fireworks and local dances in Melun and Cachan.
In Nice, ceremonies include a memorial to honour the victims.
The troop procession on the Champs-Élysées omitting the typical enrolment.
For the historic debut, Ukrainian troops are set to walk beside French forces.
Attendees can watch the procession from the boulevard no reservation needed.
The lineup further displays units from French overseas bases and veteran units.
Government bodies warn heat may affect later events.