If you are a citizen of a member state of the European Union, you will not need to obtain a visa. If you are a citizen of a country outside the European Union, you must have a visa to study at GOBELINS. There are several different long term visas available based on the duration and purpose of your stay. As a GOBELINS student you are likely going to apply for a student visa, however you may need a different one if you are going to do the course under an apprenticeship.
For more assistance with this process you can use www.diplomatie.gouv.fr/ or alternatively contact the French Embassy in your own country.