Just taken this from the manual.
4.5. Brakes
Diagonal braking circuit arrangement .
Vacuum assistance by brake servo .
Front brake discs .
Rear brake drums .
Handbrake cables acting on the rear wheels .
Automatic wear adjustment at the rear jaws .
Warning lamp of pad wear on the front caliper .
Compensator incorporated into the rear wheel cylinders or load-sensitive according to equipment . Anodised aluminium tandem master cylinder .
Brake fluid quality :
CITROEN specific fluid
Reference
Quantity : 0,5 litre