Book II: Property and the various changes in ownership

Nevertheless, when the thing joined is much more valuable than the main thing, and when it has been used without the owner’s knowledge, the owner may request that the thing joined be separated in order to be returned to him, even when this could result in some deterioration of the thing to which it was joined.

If of two things united to form a single whole, one cannot be regarded as the accessory of the other, that one is deemed to be principal which is the more considerable in value, or in volume, if the values are approximately equal.

If a craftsman or any other person has used material which did not belong to him to form a thing of a new kind, whether or not the material can return to its first form, the person who was the owner of the material has the right to reclaim the thing formed from it by reimbursing the price of the labour estimated at the date of reimbursement.

If, however, the labour were so great that it far exceeded the value of the material employed, the industry would then be deemed the principal part, and the workman would have the right to retain the thing worked, by refunding to the owner the price of the material, estimated at the date of the refund.

Where a person has used in part the material which belonged to him and in part that which did not belong to him to form a thing of a new kind, without either of the two materials being entirely destroyed, but in such a way that they cannot be separated without inconvenience, the thing is common to the two owners, in proportion, as regards the one, to the material which…

Where a thing has been formed by the mixture of several materials belonging to different owners, but none of which can be regarded as the principal material, if the materials can be separated, the one without whose knowledge the materials have been mixed may apply for their division. If the materials can no longer be separated without inconvenience, they acquire joint ownership in proportion to the quantity, quality and value…

If the material belonging to one of the owners were far superior to the other in quantity and price, in that case the owner of the material superior in value could reclaim the thing arising from the mixture by reimbursing the other for the value of his material, estimated at the date of reimbursement.

When the thing remains in common between the owners of the materials from which it was formed, it must be licensed for the common benefit.

In all cases where the owner whose material has been used, without his knowledge, to form a thing of another kind may claim ownership of that thing, he has the option of claiming the return of his material in the same kind, quantity, weight, measure and goodness, or its estimated value at the date of the return.

Those who have used materials belonging to others, and without their knowledge, may also be ordered to pay damages, if appropriate, without prejudice to proceedings by extraordinary means, if the case so requires.