Also not a Mirage, but definitely an economic sub (sub) compact, a Tata Nano CX (with airco!)
https://www.marktplaats.nl/a/auto-s/...n-bugatti.html
The owner doesn't specify it's economy, but tells a full tank costs €20, and brings you 350km. That would be 28km/l, at current prices. My estimation of the owner based on the text in this ad is that he's not exactly a hypermiler, so with some effort that could be better.