When your female Frenchie is receptive to mating then you know she is in heat. Sometimes this occurs more than twice a year. Her cycles can last between 21 and 28 days. Depending on the breed age and size the season may last for a shorter or longer period of time.
The first stage of a season is the proestrus stage followed by the estrus stage during which your buck is ready to reproduce. During the diestrus stage your buck is ready to reproduce. This is the point at which your French bulldog will no longer be interested in mating. At this point the bleeding would have stopped and the vulva would have returned to its normal size. It is at this point that the season ends.
Once your dog stops bleeding a season is not yet over. It may take her a week or more to come out of the heat.