hai..
floorplanning is starts with creating physical only pad cells and defining their location and placing them. defining size and shape (by aspect ratio) of our block. defining PG pad rings for power continuity. specifying ignored routing layers , placing the macros by following some macro placement guidelines and defining the blockages.
coming to the placement , here 1st will do some checks like placement setup checks, DFT and power set up checks and placing and legalizing the std cells and set up time optimization.
In the summery,
floorplanning is about placing the macros and blockages and leaving the uniform space for the std cells and placement is about placing and legalizing the std cells.