In France, The wrench is called "Guillemin wrench" (French: clef Guillemin, pronounced [kle ɡijəmɛ̃]), but the firefighters call it "tricoise wrench" (clef tricoise, [kle tʁikwaz]). The curved part applies on the ring, and the hooked part clutches a notch.

Big tricoise wrenches are placed in fire trucks, and are mainly used to fasten the big hoses, e.g. ∅110 mm hoses to feed the pumper tank from the hydrant (∅100 mm for the clutch). Small tricoise are made of brass and hang at the fire belts; they are used to fasten the small hoses, e.g., ∅70mm to ∅22mm hoses (∅65mm to ∅20mm clutches).

The shape is sometimes adapted so it can be used as a tool for other purposes; it is then called "polycoise wrench" or "Deschamps wrench". These tools are used to

• Open GDF standard gas enclosures and EDF standard electrical enclosures (12mm female triangle wrench);
• Open fire hydrants (15.6mm female triangle);
• Open doors without knobs, ventilation accesses and closets containing firefighting equipment in some public locations (5×5mm to 8×8mm square female wrenches);
• Open dry risers (12.5×12.5mm square female wrench);
• Open bathroom and toilet doors (screwdriver); and
• Remove nuts and bolts (13, 17 and 19mm six-point wrenches).

The shape of a hydrant wrench is sometimes adapted so it can be used as a tool for other purposes, such as:

• Storz and spanner hose couplings
• Rocker lug couplings
• Water meter shutoff valves
• Gas cock valves
• Pentagonal nuts
• Square nuts.