In the wake of the fire at Notre Dame Cathedral, Ubisoft has pledged 500,000 Euros ($564,000) to the restoration of Notre Dame. They are also giving away Assassin's Creed Unity for free. To quote their official statement on the matter:
In light of the devastating fire at the Notre-Dame de Paris, Ubisoft wants to give all gamers the chance to experience the majesty and beauty of the cathedral through Assassins Creed Unity on PC. From April 17th at 3:00pm to April 25th at 8:00am (your local time), you can download Assassins Creed Unity on PC for free via this giveaway webpage, Uplay PC or the Ubisoft Store. Note that you?ll own it forever in your Uplay games library.
We encourage all of you who want to help with the restoration and reconstruction of the Cathedral to join Ubisoft in donating.