You may need a visa for São Tomé and Príncipe if you have a French passport
Visa options for São Tomé and Príncipe
Electronic visitor visa is required for trips longer than 15 days
Travellers need a visa to visit Sao Tome and Principe for Business or Tourism for more than 15 days. Travellers do not need a visa if staying for 15 days or less. An eVisa is the fastest and easiest way of obtaining a visa for Sao Tome and Principe because travellers can submit their application and supporting documents online. Once the application is approved, travellers receive their eVisa confirmation electronically. A valid visa is required to board the flight. If the visa is expired or doesn’t match the traveller’s passport information, travellers cannot board their flight.
This is not offered by sherpa°.
Apply on the government site.