Broad beans usually have grey-green foliage and grow to about 3-4 feet.
The stems are noticeably square and about 1/2 inch across. The pods get
to 1/2 or more across.

French beans have mid-green leaves and grow to about a foot (or climb to
5' plus). Pods rarely get above 1/2 inch across.

Steve Harris - Cheltenham - Real address steve AT netservs DOT com
A useful bit of gardening software at http://www.netservs.com/garden/