Visas are not required by the following nationalities:Algeria, Bulgaria, Burkina Faso, Cape Verde, Central African Republic, Chad, Republic of the Congo, Côte D'Ivoire, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Madagascar, Mali, Mauritania, Niger, Nigeria, Rwanda, Senegal, Sierra Leone, South Africa, Taiwan, and Togo.
Visas can be single entry $40USD or multiple entry $45USD and last 30 days. Visas cost $140 for US citizens. In Paris, single entry visa costs EUR 70 for all EU citizens.
By plane
There are many international flights arriving at the main airport in Cotonou. From here you can connect to Paris, Amsterdam, Moscow, and a variety of cities in West Africa. In order to enter the country you will need proof that you have had a yellow fever shot, and this will need to be readily available at the airport.