Due to the massive volume of documents and records kept by the Archives nationales, these have been divided among four archives centres complemented by a microform centre serving as a back-up in case original documents are destroyed. The main centre is located in Le Marais in the heart of Paris, but a new centre is being built in Pierrefitte-sur-Seine, in the northern suburbs of Paris, and will become the main centre of the Archives nationales from 2012 on, the Paris premises keeping only pre-French Revolution records.