Visas are required for most nationalities.
You will require the following;
A passport valid for 60 days after the period of stay granted;
Two photographs of and of course some money (about 60 euros)
There is a visa on arrival available at Abidjan airport for 70 Euros. You will need to apply in advance and have proof of hotel booking.
Cote d'ivoire visa information.
Cote d'ivoire embassies
Cote d'ivoire visa on arrival
If you are travelling to Benin, Burkina Faso, Cote d'ivoire, Niger and Togo you may apply for a Visa Touristique Entente which costs 25000cf (about (US$50). It covers all the above countries, is cheaper and less work than getting single visas for each country.