In the free market, the parties may negotiate any period of contract. If no period is stipulated the contract is valid for an indefinite period. The contract must be in writing.
The tenant may cancel the contract at any time by giving three months’ written notice, without stating a reason. The landlord can only cancel the contract for a serious reason, such as the need to use the flat for his own family. It is common to conclude free-market leases for rather short periods, like one or two years. After that the tenant has to leave the flat. If he keeps living in the flat and the lessor does not intervene within 30 days, the contract is automatically extended, normally for another year.
Insist on a written contract
The main thing you need to remember is that everything is negotiable in the Czech Republic. Just make sure you and the lessor agree on having a signed contract at the end of the negotiation. Sometimes private lessors refuse to draw up a contract. As in many countries there is a measure of respect for a written contract, even if in practice the enforcement is difficult on both sides. If someone doesn’t want to give you a written agreement, you should reconsider whether you want to deal with them at all.
Always keep in mind that everything of importance for the rental agreement has to be stated explicitly in the contract. Not just the monthly rent but also dealings with utility costs, if included, have to be stated. In addition, any damage to the flat has to be recorded. If the owner promises to install any equipment in the apartment within the contract, make sure it is actually there the day you want to sign the contract. Otherwise you will have to pay “for the loss”. It might well happen that furniture in the flat is not mentioned in the contract. This might seem to be a stroke of luck, but don't be shocked if the lessor removes it shortly after you moved in.
Checking your rental contract
When you first get the contract, have a native speaker look it over to make sure it is not completely ridiculous. A common opening tactic in negotiations is to hand over a draft stuffed with conditions meaning you have a lot of obligations and not many rights. If it’s really excessive, hand it back and be adamant that it is unacceptable. If your lessor is still saying that it’s a fair contract, firmly pick out a couple of points and request a sensible model contract so no more time is wasted. If you do this as a foreigner you should earn some respect for not being completely clueless and end up with something sensible.
Once you receive an acceptable contract, you'll have to have it checked by a lawyer to make sure there are no subtle bear-traps hidden in there. If you’re in a small town, consider hiring a lawyer somewhere else to avoid paying a lawyer who happens to be your new landlord’s drinking buddy. Signing a contract without a legal opinion is not recommended.
You will need to pay the landlord a deposit. Don’t count on seeing it again. You may be asked to pay 6 months rent in advance.