The German system (and all those based on it) takes from the theory of title and the Roman mode the distinction between the contract and the act of subsequent transmission. However, it has a substantial difference with the Roman system, which consists of the total abstraction of the act of transmission with respect to the previous contract. Thus, while in systems such as the Spanish one, the cancellation of the contract can cause the loss of the property by the buyer, in Germany the invalidity of the previous contract or even its non-existence does not affect the transfer of ownership.[7]​.

Cuena Casas, Matilde (1996). Function of the power of disposal in systems of onerous transmission of real rights. Barcelona, ​​J.M. Bosch.

Contenido

A pesar de que el Código civil español está claramente inspirado en el Código francés (que no recoge la teoría del título y el modo y en el que los contratos bastan para transmitir la propiedad), el sistema de transmisión de la propiedad español mantiene en lo esencial el sistema romano.[4]​.

El artículo 609.2 de Código civil español establece que “la propiedad y los demás derechos reales se adquieren y se transmiten por la ley, por donación, por sucesión testada e intestada, y por consecuencia de ciertos contratos mediante la tradición "Tradición (Derecho)")". La tradición es la entrega de la cosa cumpliendo ciertos requisitos, y es precisamente la alusión a la misma la que introduce la teoría del título y el modo en el ordenamiento español (ya que no señala que la propiedad se transmite mediante los contratos sino “mediante la tradición”, por consecuencia de esos contratos).

En el Derecho español la entrega física de la cosa no es siempre necesaria. En primer lugar, porque a veces es simplemente imposible (no se puede entregar una finca) y en segundo lugar, porque en ocasiones es complicado entregar la cosa y la ley permite un modo más sencillo de transmitir la propiedad.

Así, el modo (la entrega) puede consistir en diferentes actos:.

Relationship with other private law institutions

If the transfer of ownership is based on the theory of title and manner, it is perfectly valid to enter into a contract of sale to sell a thing that is not the property of the seller; This is what happens in Spanish Law. In this case, the sales contract is valid, but the seller will be obliged to deliver something that is not his. In this situation there are three options:

In conclusion, the contract of sale of a thing that is not the property of the seller is valid, because the seller has to be the owner when he delivers the thing, but does not have to be the owner when he signs the contract.[5]​.

A buyer can never be completely sure that the seller was the true owner of the thing he bought. Your purchase and sale contract will be valid and if you lose the thing at the hands of its true owner, you can always sue the seller and recover the price you paid, but you will not be able to keep the thing.

For this reason, the law includes the figure of usucapion or acquisitive prescription, which allows the buyer to be protected when the delivery of the thing did not cause the transfer of ownership because the seller was not the owner. Thus, if a contract of sale was concluded and then the thing was delivered that did not belong to the seller, ownership was not transferred, but the law establishes that, after a time, the thing becomes the property of the buyer, so that its legitimate owner will no longer be able to claim it (because, in reality, he has ceased to be the owner). This period is three years for movable property and ten for real estate (aa. 1955 and 1957 of the Civil Code). All of the above refers to "ordinary" usucapion, which should not be confused with "extraordinary" usucapion (with a much longer term and which only requires possession of the thing, regardless of the title).

Regarding the theory of title and mode, adverse possession protects only from the lack of requirements of the mode and never from problems with the title. Thus, if the sales contract is annulled (for example because the seller signed it under threats), the buyer will be forced to return the thing, regardless of the period that has passed.[6]​.

The German system (and all those based on it) takes from the theory of title and the Roman mode the distinction between the contract and the act of subsequent transmission. However, it has a substantial difference with the Roman system, which consists of the total abstraction of the act of transmission with respect to the previous contract. Thus, while in systems such as the Spanish one, the cancellation of the contract can cause the loss of the property by the buyer, in Germany the invalidity of the previous contract or even its non-existence does not affect the transfer of ownership.[7]​.

Cuena Casas, Matilde (1996). Function of the power of disposal in systems of onerous transmission of real rights. Barcelona, ​​J.M. Bosch.