The Tour's final leg - stage 21 when cyclists enter Paris and do laps around the Champs-Élysées - will be shortened to 89 kilometres instead of the 133 kms originally planned.
"As numerous wildfires are currently affecting France, particularly the Gironde region, emergency services are fully mobilised to combat the blazes, while internal security forces are working to secure the affected areas and protect the population," the Paris police and the event's organisers said in a joint statement.
"In light of this, the Interior Ministry has decided to redeploy a portion of the internal security forces initially mobilised to ensure security for the final stage of the Tour de France, in order to reinforce the response efforts in the areas affected by the wildfires."
Slovenian four-times champion Tadej Pogacar had a nearly insurmountable lead in his quest for a third straight Tour de France title going into Saturday's stage 20.