I think the best option if you're selling BTC for fiat at the lowest fees is to use Binance or Kucoin P2P exchange if you don't mind undergoing KYC verification.
I have used Binance P2P and zero fees are charged if you use the platform to exchange BTC to Fiat or Euro for your case. All you have to worry about are the rates at which traders are buying the BTC.

1. Binance P2P -  https://c2c.binance.com/en/trade/sell/BTC
2. Kucoin P2P - https://www.kucoin.com/otc/sell/BTC-EUR