This thread is old, but since it shown first in google results, I'll add previous answer with infromation from posudka.ru forum:
De buyer frying pans series Carbone plus, Force blue, la Lyonnaise, and Mineral B are all made of carbon steel. Difference between "white" and "blue" steels is that last one made with blueing process. So difference is mostly decorative.
These 4 series of pans differ by thickness of material used:
la Lyonnaise - from 1 to 1,5 millimeters
Force blue - 2 mm
Mineral B - 2,5 mm
Carbone plus - from 2,5 to 3 mm.
Thicker material of pan provides slower heating and more even heat distribution.
Besides, forms and accessories differs.
In functional point of view carbon steel is similar to cast iron. It has relatevely good thermo-distributing and thermo-accumulating properties. But it suffers from currosion. Thus it is forbidden to store food in these pans (in fridge for example) since is causes corrosion. These pans has NO non-stick properties, so oil should be used everytime you cook.
Carbon steel pans are good for frying steakes and other beef and pork dishes. With some practice they are good for other products to cook.
Carbon steel pans are siutable for all cooking surfaces - gas, electro, ceramics and induction. They are good for ovens too. But it is forbidden to put them in dishwasher.
(sorry for mistakes in tranlation and hello from Moscow!)