A method for monitoring the leaktightness of sealed products is provided, including: a charging stage during which at least one sealed product containing a tracer gas is placed in a chamber under atmospheric pressure; a pre-evacuation stage during which the chamber containing the at least one sealed product is brought into communication with a buffer volume under a subatmospheric pressure for a pre-evacuation time of less than 0.5 second; and bringing the chamber into communication with an analysis line arranged to bypass the buffer volume in order to measure a concentration of the tracer gas in the chamber so as to detect a leak from the at least one sealed product. An installation for the detection of leaks for implementing the method is also provided.