As you may have heard on the news, France's most iconic cathedral, the Notre Dame, had caught fire on April 16th. In order to spread the news of the restoration fund, Ubisoft - the French game publisher, is offering free copies of 'Assassin's Creed Unity'. This game is supported on the Xbox, PC, and PlayStation 4 platforms. This is starting from the 17th April to midnight on the 25th April. They're also encouraging people to donate to the restoration effort.
There are many Assassin's Creed games, but this one in particular (Assassin's Creed Unity) takes place in Paris during the French Revolution. The game is being given away as the Notre Dame is a bold attribute in the game. When the game launched originally, it didn't get the best reviews. Many people complained about a 'buggy launch' and the lack of significant modern day progression. There were also arguments that the development team didn't add female characters to the multiplayer mode.
After you've done so, you have an option to add the game to your collection and even stream the game for free as well. On the Ubisoft store, there should be a link for you to press to stream.