This invention concerns a system for the attachment of an information sensor opposite to, and at an air gap's distance from, the coder of a bearing, with the system including a cap to be associated with a ring that at least partly covers the coder, where, in combination, the cap includes at least one device for attachment of the sensor to the internal surface of the cap and one device for electrical connection of the sensor. The invention also concerns a sensor designed to be attached to such a system, an ensemble formed by the attachment system and the associated sensor, as well as a bearing equipped with such an ensemble.