Before you start this project and contract, remember to know about the legal.
You have to consider that there is a copyright law, release form and public liability insurance etc.
The dictionary meaning of the law is the social norms of state power.
Legal constraints meaning is that your project may be constrained by a variety of licensure and other actions, based on the industry and activities the project wants to pursue.
You cannot to do thing belong to legal constraints like wrongful discharge and discrimination against workers.
And you must to do within the legal constraints that govern them to avoid potentially costly legal breach.
Otherwise you will have to pay a fine.