Contract of sale is a remunerative type of contract. It is a legal title (titulus) for acquiring ownership. The purchase contract creates an obligation for the seller to hand over the object of purchase to the buyer, and for the buyer to take over the object of purchase and pay the seller the agreed price for it. A purchase contract is a classic two-party contractual relationship, where the seller acts on one side and the buyer on the other. Conceptual signs of a purchase contract include the subject of the purchase and the purchase price. These are essential components of the purchase contract, on which the contracting parties must agree in order for the purchase contract to be concluded. For contracts on the transfer of real estate, the Civil Code requires a written form, otherwise it is invalid and it is an absolute nullity.
Purchase contract in accordance with § 42 par. 2 of the Act on Real Estate Cadastre contains the designation:
a) participants of rights to real estate; if it is a natural person, first name, surname, maiden name, date of birth, birth number and place of permanent residence, if it is a legal entity, name, registered office and identification number, if it has been assigned, or other identification data,
b) of the legal act and its subject, place and time of the legal act,
c) real estate according to the cadastral territory, land according to the parcel number registered in the set of descriptive information, land registered as a parcel of register "C" or a parcel of register "E", type of land and area of land, inventory number of the building and parcel number of the land on which the building is located built, apartment or non-residential space numbers, floor numbers, entrance numbers and co-ownership share in the common parts and common facilities of the house and on the land, or on the adjacent land, inventory number of the building and parcel number of the land on which the house is built; if the property is co-owned by several owners, the share expressed as a fraction of the whole is also indicated.
Pursuant to § 42 par. 3 of the Real Estate Cadastre Act, the transferor's signature must be officially certified. In the case of buying an apartment, it is necessary to ensure that the conditions according to the Act on the ownership of apartments and non-residential premises are also met:
The contract on the transfer of ownership of the apartment and the contract on the transfer of ownership of the non-residential space in the house must be in writing and, in addition to the general requirements 9) must contain
a) description of the apartment or non-residential space in the house and accessories of the apartment, 5) definition of the location of the apartment or non-residential space in the house by indicating the apartment number, entrance number and description of the non-residential space, determining the extent of the floor area and equipment of the apartment and non-residential space in the house,
b) definition of the size of the co-ownership share of the owner of the apartment or non-residential space in the house on the common parts of the house, common facilities of the house, on accessories, on the land built by the house and on the adjacent land, while the size of the co-ownership share is determined by the share of the floor area of the apartment or non-residential space to the total floor area the areas of all apartments and non-residential spaces in the house, if the adjacent plot is not followed in accordance with letter e),
c) determination and description of common parts of the house, common facilities of the house, accessories and adjacent land and, if applicable, determination of which common parts of the house and common facilities of the house, parts of accessories and adjacent land are used only by some owners of apartments and some owners of non-residential premises,
d) adjustment of rights to the land built on by the house and to the adjacent land,
e) definition of the size of the co-ownership share on the adjacent land by agreement between the purchaser of the apartment or non-residential space and the owner of the house,
f) declaration of the acquirer of an apartment or non-residential space in the house on accession to the contract on the association of owners or to the contract on the performance of administration,
g) adjustment of rights to civil protection facilities, if such objects are in the house, after prior approval of the competent authorities.
The annex to the contract on the transfer of ownership of an apartment or the contract on the transfer of ownership of a non-residential space is a confirmation by the administrator or the chairman of the association of owners of apartments and non-residential spaces in the house that the owner of the apartment or non-residential space in the house has no arrears in payments for services connected with the use of the apartment or non-residential space in the house and on the creation of an operation, maintenance and repair fund; this does not apply if it is the first transfer of ownership of an apartment or non-residential space in a house.