If you sell through an agent, you should not accept commission of more than 5%. (IMHO)
Plus valia tax - payable to the local town hall; should be negligible, possibly zero, since you've had the property little more than a year. You can go to the town hall yourself to get the bill.
Capital Gains Tax: if you're non-resident, 3% of the sale price will be retained at the notary in lieu of any CGT due, which is 18% of any paper gain you make (less original purchasing costs). If the gain is zero (or negative) you can claim back the 3%.
Bank charges - if there's a mortgage to be cancelled there may be fees; if your bank wants to charge you for depositing the proceeds, negotiate!
Other than these, the costs involved should be met by the buyer. I can't think of any other costs you would incur, unless you choose to use a legal representative. Not really necessary in my opinion, especially if you sell through an agent - make them do the work!