Several physical and behavioral indicators indicate your French Bulldog is in heat. For instance, it will generally pee more than normal, and there'll be a blood-tinged discharge and an enlarged vulva. Your Frenchie can also appear anxious, distracted, and more attentive to male dog's attention. She may encourage sexual contact, such as lifting and shifting her tail to the side, commonly known as flagging. Well, if French Bulldogs had tails, she would be doing this. :) The discharge begins with darker blood and then progressively lightens to pinkish colour. The heat period lasts for around three weeks. Sometimes this period can be longer than a week; some French Bulldogs can become pregnant at the end of the first week.