You need a visa for Papua New Guinea if you have a French passport
Visa options for Papua New Guinea
Electronic visitor visa
Travellers need a visa to visit Papua New Guinea for Business or Tourism. A Papua New Guinea eVisa is the fastest and easiest way of obtaining a visa for Papua New Guinea 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 will not be able to board their flight.
This is not offered by sherpa°.
Apply on the government site.