Keep patience with this car and it will give u 23-24kmpl as u drive on long routes.
M also using 205 but mostly city driving in dense traffic of karachi:D
Still manage to get 17-18kmpl with Ac.
Switch to ECO mode if running on PWR or normal mode.
Try to accelerate normally and keep in first half of ECO bar as much as u can.
Avoid hard braking and give ure car sufficient time to brake so ure battery gets more charge than abrupt braking.
Use AC according to ure requirement and not on climate control 
Check tyre air pressure and keep 30psi in all
Switch engine oil to 5w30
Check spark plugs and if worn then buy new ones oem
For checking battery I did one physical experiment. Drove the car in PWR mode without AC at high speeds of 120-130 (very heavy foot). So when the battery was charged full (all the bars filled in battery icon) I came to a halt, reset trip meter, switch to ECO mode then EV) electric vehicle) , AC off and drove as lightly as I could till the EV icon flashed and disappeared. Noted the distance travelled. Also make sure that u do not cross 60kmph on EV or else's Ev will deactivate.
Unfortunately I don't remember the figure as I did this in winter.
Will do again and post here.