CITROËN C4 Picasso Owner's Handbook Manual page 313

Checks
Quality of the fuel used for
petrol engines
The petrol engines are perfectly compatible
with E10 or E24 type petrol biofuels (containing
10 % or 24 % ethanol), conforming to European
standards EN 228 and EN 15376.
E85 type fuels (containing up to 85 % ethanol)
are reserved exclusively for vehicles marketed
for the use of this type of fuel (BioFlex
vehicles). The quality of the ethanol must
comply with European standard EN 15293.
316
Quality of the fuel used for
Diesel engines
The Diesel engines are perfectly compatible
with biofuels which conform to current and
future European standards (Diesel fuel which
complies with standard EN 590 mixed with a
biofuel which complies with standard EN 14214)
available at the pumps (containing up to 7 %
Fatty Acid Methyl Ester).
The B30 biofuel can be used in certain Diesel
engines; however, this use is subject to strict
application of the special servicing conditions.
Contact a CITROËN dealer or a qualified
workshop.
The use of any other type of (bio)fuel
(vegetable or animal oils, pure or diluted,
domestic fuel...) is strictly prohibited (risk of
damage to the engine and fuel system).