The first CSeries aircraft has received the Canadian tail number C-FBCS and was registered with Transport Canada on May 6th.
As is common with Bombardier aircraft, the official designation of the CSeries is nothing like its marketing designation. The CS100 is actually a model BD-500-1A10 and the CS300 will be the model BD-500-1A11. These designations are very close to Bombardier's business jets, the Challenger 300 (BD-100-1A10), Global Express (BD-700-1A10), and Global 5000 (BD-700-1A11).
As is also common with Bombardier aircraft, the first serial number for the CSeries will begin with the seemingly arbitrary number 50001.
First flight of the CS100 is expected within months if not weeks.