Participants should secure accommodation by themselves. The internet booking services as well as Airbnb have good selection for the Helsinki region
Google Hotel Search: https://www.google.com/travel/hotels
Scandic Hotels offers 10 % discount with the booking code FIARB. Click “Booking code, Bonus Cheque or Reward night” and add the code FIARB to the textbox “Add booking code”.
Some recommended hotels nearby the meeting venue: