Need some info

First question: landlord pays the connection fee, unless your lease says otherwise. Every lease agreement contains a definition of what you are supposed to pay and the connection fee is not within this definition. Water, electricity and gas are basic services and every rented flat is supposed to have them. Internet and phone is different, they are not part of the minimum essential services required by law for a flat to be deemed fit for residential use (your lease agreement has some annexes that contain these rules - it is required by law that you receive such annexes).

Note that the 150 fee is due only in two circumstances: new flats being connected to the grid for the first time or flats for which the landlord has decided to close the meters instead of subscribing to the special electricity billing system for empty houses. Most likely he decided to close the meters or failed to make the necessary paperwork, you are not supposed to pay for his mistakes.

Second question: prices are freely set by the parties, of course he cannot increase the rent after having signed the lease. Note that lease agreements of three or nine years do not require you to stay for the entire duration of the lease. These are the rules:

You leave the first year: three months prior notice + 3 months of rent as penalty
You leave the second year: three months prior notice + 2 months of rent as penalty
You leave the third year: three months prior notice + 1 month of rent as penalty
You leave after the third year: three months prior notice.

However, in a lease of less than three years you have to stay for the entire duration of the lease, i.e. if you leave, you have to pay anyway until your lease expires. Actually, for some people a nine year lease is more flexible than a short-term lease.

Thanks David for this info.
Can you point me to some official documentation or website where I could see the rights of tenants and samples of annexes that must be a part of the agreement?