In order for this agreement to fulfill the purpose for which it is to be concluded it must be signed by the parties before starting cooperation. Typically a confidentiality agreement precedes the conclusion of the target main agreement e.g. a service provision agreement. Moreover the NDA agreement may but does not have to be additionally supplemented with a confidentiality clause which usually appears as a separate provision in the target agreement or replaced by it completely.
Confidentiality agreement is not regulated in Polish law however on the basis of from Art. of the Act of April - Civil Code according to philippines photo editor which the parties concluding a contract may arrange a legal relationship at their discretion provided that its content or purpose does not contradict the properties nature relationship statute or principles of social coexistence – in accordance with the will of both parties.
Also check: More about the principle of freedom of contract can be found here. In turn the purpose of confidentiality clause is also to secure data and business secrets during the term of the main contract. However the confidentiality clause is usually an element of a civil law contract or an annex to it. Compared to an NDA a confidentiality clause is usually a narrower provision for the protection of all company data and information.