A cesión de derechos transfers the possession or use rights someone holds over a piece of land. It does not transfer ownership: it moves whatever the assignor has, without creating registered title in your name. Used for land sales, it is the instrument behind most Mexican land fraud.
In practice
The device has narrow legitimate uses — transfers between ejidatarios inside their own ejido, or assigning rights under an existing contract with the parties' consent. The trouble starts when it is presented to a buyer as a sale: official-looking paper, a price far below market, urgency, and the line that "this is how land is bought around here."
It is not. A real estate purchase in Mexico closes before a notario and ends in an escritura pública registered at the Public Registry of Property. If a cesión de derechos is the instrument you are being offered for land, stop. Ask for two things: the folio real for the parcel and, where the land has ejidal origins, the dominio pleno resolution together with its registration. Without those, there is no deal worth doing.
Watch out for
Three failures repeat. No registration: nothing appears at the Public Registry, so your claim is invisible to any third party. Double sales: the same rights can be assigned to several buyers, and they are. No practical recourse: litigating an unregistered paper takes years and rarely returns the money. Add the variant where fake intermediaries or forged powers of attorney collect deposits and disappear.
If you have already signed something like this, the way out is not signing more paper: take the whole file to a real-estate attorney and a notario, and check the Public Registry for what actually exists and in whose name. And if it is merely being offered to you, the decision is simpler still — don't pay.
Related: Ejido · Dominio pleno · Escritura pública · Full guide: ejido land risks