What is the legal standard for assessing lawyer's fees in the absence of an agreement or a dispute over it?

Lawyer's fees and the method of their payment are determined by an agreement concluded between the lawyer and their client. If no agreement exists, or if the agreement is disputed or void, the competent judicial authority shall undertake their assessment upon the request of either party, taking into consideration the effort expended and the benefit achieved. This provision also applies to ancillary claims arising from the original lawsuit.