You will find that there is a great deal of variability among surgeons regarding this (and other postoperative) recommendations.
Remembering that your goals are (hopefully) to be safe and to look the very best you can after your Brazilian Butt Lift, the only right thing for you to do is to ask the surgeon you have chosen to do the surgery on you what their preference is for your exercise regimen. This is the best way to assure that what you do fits with the overall plan and recovery process which has allowed your surgeon to achieve success in the past.
If you have not yet chosen your surgeon and are asking because you are interested in learning about what is involved in the procedure should you choose to proceed with further inquiries about it, I would say that you should FIRST identify a surgeon or two with whom you would like to meet for consultations- choose them based on their educations, training, experience, talent and outcomes, and not on price or marketing gimmicks.
During these visits, ask them about the details (like when you can workout). But don't choose a surgeon based on when they'll let you workout either- choose the surgeon you like, feel you can trust, and whose outcomes and skills demonstrate the attention to safety, quality, and artistry you desire.