This is a Sonic Riders promotional leaflet. It's sort of like a mini-booklet given away to promote the game, likely in game shops before the game was on sale. You can see the Babylon Rogues, several screenshots and descriptions.

What exactly does it say? You can't read it because it's all in Japanese. Still, giving away a booklet is a good idea to get information out on an upcoming game. It also makes for an interesting collectible.