Thursday 01 Jan New Year's Day
Friday 03 Apr Good Friday Monday 06 Apr Easter Monday Friday 01 May Labour Day Friday 25 Dec Christmas Day
Note: On Thursday 24 December 2015 (Christmas Eve) and on Thursday 31 December 2015 (New Year’s Eve), trading on the Cash markets will be half day trading with all instruments closing by 14:05 CET. Contracts on the Derivatives markets will close at various times, commencing at 13:55 CET.
Source: https://www.euronext.com/en/trading/trading-hours-and-holidays