Carnival in Maresme (and across Catalonia) is known as Carnestoltes is traditionally celebrated the week before Lent. However, the origins of Carnival seem to date as far back as the Roman times and their festivals, later on integrated in the Christian calendar as a way to let people get a bit wild before they were made to fast and sacrifice for the upcoming 40 days of Lent. The weekend of the 8-10th February is a time for partying in Maresme. Festivities normally start a week before and each town and village will have their own activities.
The best place to look for events in local villages is https://www.turismemaresme.cat/es/descubre/agenda/