Amount of the broker's commission
The amount of the broker's commission is a matter of negotiation. In principle, the Code of Obligations defines neither the method of calculation nor the amount of the commission to be paid. However, a disproportionately high commission can be reduced at the debtor's request. Whether, and from what moment, a commission is owed to the broker depends on the form of the contract.
Brokerage contract as a special form of contract
The brokerage contract is a special form of contract. It may be limited to the identification of interested parties (identification broker) or it may be directed towards the mediation between seller and buyer (intermediary broker). For the latter, the broker must actively promote the closing. This regulation is one of the key points of the brokerage contract. It depends in advance on how you have formulated the assignment to the broker.
In your case, it is therefore decisive what is meant by a customer "handled" by the broker. The more actions the commissioned broker performed, the more likely his contribution to the mediation is to be affirmed. If the broker's efforts comprise nothing more than the delivery of the sales documentation, it can hardly be said that he acted as an intermediary and the commission would only be owed if the mere proof of a prospective buyer was sufficient.
The broker's salary is performance-related. It is therefore owed if the conclusion of the contract between the seller and the third party is due to the fact that the broker has performed an activity in the agreed manner. If the broker can conclusively demonstrate a connection between his activity and the conclusion of the contract, he is entitled to full remuneration. It is sufficient if there is at least a psychological connection between the broker's efforts and the third party's decision in the sense that the motive was co-determining for the contracting party's willingness to conclude the contract.
The burden of proof lies with the broker
The burden of proof for the psychological connection lies with the broker, who derives his wage claim from it (Art. 8 CC). If the broker proves to have undertaken efforts that were in themselves suitable to have a determining influence on the opposing party, the general experience of life indicates a factual presumption of the psychological connection (Federal Supreme Court ruling 2C_638/2020 of 25.02.2021, E. 3.3.3).
In the case of a broker who provides evidence, the required causal connection is given if he is the first to point out the prospective buyer or seller. For this reason, the broker is well advised to document the client periodically and at the end of the assignment with a list of all (even the most non-binding) enquiries.
Provided that he can later prove the initial enquiry, perhaps even further contacts, the broker will probably succeed in successfully asserting his claim for commission. According to what has been said, the delivery of sales documentation may also be sufficient for claiming compensation. The claim definitely arises with the public notarisation of the purchase contract at the notary.
Do you have questions about contract law? Our lawyers will be happy to provide you with information.