The standard commercial lease in Buenos Aires is three years with an additional two year renewal which is triggered by the tenant requesting such in writing at least 90 days before the end of the original three year term. The price of the rent is ALWAYS negotiated in advance and clearly stipulated for the entire five year term of the contract. Commercial contracts can be terminated by the tenant after one year with a penalty of one month's rent. Why anyone would agree to a contract that deviates from these standard practices (which protect the tenant) is hard to comprehend. In the case of your friend, he should apply the same method I recommended to the OP; tell the landlord you will only pay 20-25% increase per year and if he refuses keep paying him such amount and make him initiate legal action to attempt to remove you from the premises. This will take at least a year and the landlord will not want to deal with this.
Another point on this - commercial or private, no part of a contract can be legally entered into that contradicts the laws related to rental agreements (i.e., that part of the contract that is contradictory, to either party, is null and void). The legal code pretty well specifies what the common terms of just about every type of contract (not just rental) should hold and I believe that the notice period on both types of rental contracts and for both the lessor and the lessee are indeed specified in the law. They can bitch all they want, but the parts of a contract that do not match up with the legal code are null and void. It doesn't mean that you can't put something in the contract that doesn't exist in the law's boilerplate; for example, garantias aren't required by law, they have just become a standard practice due to the very laws people are referring to about how hard it is to get someone out of an apartment. The same about the 20% increase per year.
But if you agreed to a certain rate (and rates are not specified in the legal code - yet) and a certain amount of inflation increase, the owner is just SOL if he's asking for more. He can't force you to pay that, it's extortion.
Of course, anything that is NOT written in the contract and doesn't oppose the law, as far as agreement goes, is null and void at the end of the contract. If this guy is trying to raise the rents and you have passed the end of the contract term, he is well within his rights to demand a raise - to what he feels is proper fair value. If he wants to double it and you don't have a contract any more, you are still beholden to either agree or vacate, technically (within the proper notice periods required by the contract law on BOTH sides, of course - if you were to go month-to-month after signing a contract and the term ends, I believe that any parts of the contract that are in agreement with the law actually continue in force after the contract itself expires).
Absent contract in any type of transaction here, under whichever specific part of the law the particular transactions occur, the contract law holds sway always. It's one of the reasons people can work in the black and not be illegal, but the employer can get in trouble because the law spells out the duties on both sides and it is incumbent upon the businesses (when employing someone directly) to take care of most of the issues of employment (withholding, aguinaldo, etc). The only thing the employee is responsible for, really, is showing up and doing his job (and even sometimes that is enforced on a very hit-and-miss [mostly miss] basis when talking about the employee).
Most of the above I actually learned from helping my sister-in-law through two years of Law in high school (she took the "empressarial" branch of study). I'm not an expert, but I'm not just talking from hearsay.
Something that I am pretty sure of but won't swear to, is that if an owner makes a 6 month contract with a renter, and then another six month contract at the end of that (i.e., continuous occupation with the owner's consent for more than six months), the contract under law automatically converts to a long-term 2-year lease. That has been explained to me by a lawyer and a couple of real estate agents. I have tried a couple of times to enter into these continuous 6 month contracts, is why it's come up with me. Owners (and even inmobiliarias) will do it, but I don't think they understand the law, or don't care. I've found some that will do it, but my problem is I have an apartment full of furniture (apartment I rent has to be empty) and need a lot of space (4 people, office, and a huge family that visits!) and it's harder to find a 6 month contract with that criteria anyway.
There are some pretty big differences between (maximum) 6 month rental agreements and 2-year long-term agreements. One of the biggest is supposed to be the easier ability to remove renters who occupy the premises of an apartment under a short-term lease as opposed to the extra-difficulty required with long-term leases. It's one of the reasons some owners get into trouble and CAN'T get someone out of a short term lease, because the owner has inadvertently converted his contract from short-term to long-term. And of course, any time a child is involved as one of the occupants, all bets are off anyway...
The renter has extremely strong rights in Argentina. Don't let the owner take advantage of you. You do have rights as the lessee, even as a foreigner, and I don't think you'd end up in any problems with the law as long as you are following the terms of the contract (i.e., you can't just stop paying and comply if the owner is doing something you don't like, but keep paying and you are totally in the right.) I am pretty sure that even follows with things like the landlord won't pay to fix something that is his responsibility (sometimes may be hard to determine exactly what that is) and you withhold the price you paid to fix something that was his responsibility from the rent, accompanied by whatever you need under the law to prove it; i.e., proof that you requested the fix, non-compliance on the owner's part (the contract specifies the time within which the landlord has to fix things), inclusion of receipts for the work/replacement parts, etc.
I gripe about the inflation a lot here, but mostly that's my fault for living in an expensive place (both rent-wise and daily living costs).
The thing that gets me most, though, is the requirement that the majority of owners have to require a garantia. It's ruinous in terms of stress and time for foreigners particularly because it's so damned difficult to get around that sometimes (I'm sure for Argentinos as well, sometimes, but Argentinos have family here from which they can draw on, foreigners usually don't and it can take years to build up relationships that can be used to request the loan of a garantia, and I'm not talking about purchasing a garantia from strangers - I looked into that once and although it seems possible, it's a bit shady and could be problematic getting it approved for the contract for a number of reasons. At least one bank also provides bonds, but you then have to have a bank account with credit [not just a savings account, which means some medium-term history] and they have a narrower window related to the amount you make, to be proved officially, and how much they will guarantee...).
I find myself in the position after nearly four years to have to vacate my current apartment (I still have 5 months, nothing bad on the part of the owner) because the owner wants to raise the rent to nearly double what I'm currently paying. He gave me plenty of notice, and I had a really sweet deal up until now - and I can't even blame him (rates in my area went up a lot over the last two years and we didn't rewrite the second contract - I'm paying month-to-month with the original contract still in force), but here I am again looking at wonderful (and cheaper, bigger) apartments and the only thing that is keeping me from signing a rental agreement without any more thought than "can I afford it?" is that double-damned garantia...
Paraguay always looks good to me when this crap comes around. Paraguay is "you don't pay, you don't stay." Something I can understand and agree with
