I used to drive the 10th generation Civic 1.5 TCP. My wife now drives the 11th gen RS version.

What I've noticed is that the fuel consumption seems worse in the new car. I used to average around 11km/L, mostly city driving (so quite a bit of traffic jam daily).

She's averaging around 9.0-10.0km/L. Also city driving. Tyres are the same (Michelin PS4).

Is this something that's to be expected?

Yes but I didn't think it would account for such a drastic change in fuel consumption.

But the other poster above may be right about driving style and routes. I drive fast, but hardly need to brake when you also anticipate what lies ahead well. So perhaps my wife is different (lol).