Commission is the dominant model worldwide, but who pays it and how much varies dramatically by country, so establish both before you engage anyone. In some markets the seller pays the full commission, in others the buyer and seller split it, and in a few the buyer's agent charges the buyer directly. Flat-fee and hourly buyer's-agent models exist in some places too. Whatever the local custom, get the figure, the payer, and the trigger point in writing early.
On contracts, read for these clauses: exclusivity, meaning whether you are barred from using other agents or buying privately, and for how long; the tail period, under which the agent claims commission on any property they showed you even after the contract ends; automatic renewal terms; and cancellation conditions.
Never sign a representation agreement presented as a formality at a first meeting. Take it away, have it translated if needed, and remember that commission is typically earned at completion, so be wary of anyone demanding substantial money earlier.