The Federal Zone is the beach front property up to 20 meters inland that not even Mexican citizens can own. Under the Federal Maritime Land Zone Law this part of the Mexican territory belongs to the Federal Government. If any foreigner or Mexican citizen was to make use of the land, they must request a concession from the Federal Government who will charge a fee which depends on the use that the portion of the property will be given. The concession is only temporary and the government may renew them for specific periods of time.
If the concession land will not have construction on it for example a garden or just landscape, you may have no fee. For a small construction like a pool, or a deck, the Federal Zone Fee could be around $50.00 a month. The more construction there is on the concession land the higher the fees will be. It is not recommended that your home be a 100% inside the federal zone, the lower the % of property in the federal zone the better off you will be, you can have a Bank Trust property and add 20% to the land by a concession if you really want to be that close to the beach.