I don't remember who put this on the sims3 forum but I save it for future reference.
Commercial Building/minimum sized lot needed for it
Any Mausoleum/ 10x7
City Hall (Big)/ 50x21
City Hall(small)/ 32x21
School/ 35x21
Hospital/ 33x26
Bookstore/ 15x10
Corporate Towers/ 23x22
Supermarket/ 17x13
Military Base/ 42x42
Diner/ 18x11
Glass Dome/ 58x51
Science (or soil and water research)/ 35x21
Bistro/ 15x14
Stadium/ 50x32
Warehouse/ 22x22
Police/21x19
Spa/ 14x12
Community Theatre/ 24x17
