CITROËN C3 Handbook page 176

Driving
Memorising the speed
F Switch on the speed limiter / cruise control.
Speed limiter / cruise control information is
displayed.
On detection of a speed limit sign, the system
displays the speed limit value and a message
offering to make it a new speed setting.
"MEM" flashes in the screen for a few seconds.
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If the difference between the speed setting
and the speed displayed by the recognition
system is less than 6 mph (10 km/h), the
MEM symbol is not displayed.
F Make an initial press on this
button to request saving of the
speed suggested.
A message invites you to confirm the request
by pressing again.
F Press this button again to confirm
and save the new speed setting.
After a predetermined period, the screen
returns to the current display.