Agent / Management charges in Warsaw, Poland

can anybody give me an idea to what percentage of rent an agent in warsaw would normally take for managing and renting out my flat.

if you find a flat for 1500PLN the agent takes 100%(=1500zł) +22%VAT

Think you must mean 10% otherwise what's the point in renting it out?

Agent finding a flat in exchange for commision equal to one months rent + 22%

so: 1500zł + 22VAT
The commision shall be payable on the day of signing the rent agreement

In relation to ongoing management of apartments, i hear that the rates are generally from about 7 % to 10 %. And you will probably need to add the VAT on top of that. This charge can be written off against your tax liability.

There is a two possibility.
The first one is of course -equal 1 monthly rent + 22% VAT.
The second is 7-10% of each month rent, which is going to be for entire period of renting.But that does not mean or obligate the real estate agency to provide management services.