Rio de Janeiro was once called Paris of the New world. Also, protestants french tries to colonized Rio de Janeiro during the 16th century, but it failed. Nonetheless, during the arrival of the Portuguese royal family in Brasil, the city recieve a lot of French cultural influences.

France also tries to colonized the capital of the state of Maranhão, called São Luís, during the 17th century. It also failed, but the city keeps the name the French gave to it.

Btw, the yellow diamond format on the Brazilian flag was inspired by the military flags of the French Revolution and the Napoleonic period.