well i will let you find out as i never let the car get under half a tank 
Fuel tank capacity (Reference) 43 L (11.4 gal., 9.5 lmp.gal.)
I think you have interpeted the manual wrong.felixis said:The answer is simple.
The hybrid system will prevent starting the engine, unless You have at least 7.5 L of fuel in the tank.
See page 94 in the Owner manual:-
■ Running out of fuel
When the vehicle has run out of fuel and the system can not be started,
Refuel the vehicle with at least enough gasoline to the low fuel level
Warning light (P. 598). If there is only a small amount of fuel, the
Hybrid system may not be able to start. (The standard amount of fuel is about
7.5 L [2.0 gal., 1.7 Imp.gal.], When the vehicle is on a level surface. This value
May vary when the vehicle is on a slope. Add extra fuel when the vehicle is
inclined.)
RTFM (Read The F*****g Manual...)
I don't understand I could only do 35,3 liters then.DutCHR said:On the German C-HR forum someone had this issue.. low on fuel and on the way to fill her up.. the ICE stopped wthout any notification.
He was very lucky to make slowly the last KMs on the EV battery and drove into tankstation with 1 EV bar left..
Amount of liter that went in: 42,87L.
Because if you wait until it's almost empty you only have to fuel up half the number of timesKarmalakas said:Why not just refuel on every opportunity when there's less than a half tank of fuel left? It's even not advisable to drive with very little fuel in a tank.
When I refuel immediately after the warning light is lit, I can get in 35 liters.DutCHR said:How much fuel you get in at that moment?