That looks like the typical "concept car" which never makes it to the real world. It appears to be a 2 person city car which will have limited usefulness.

Now if you want a "real" diesel hybrid which is already past the concept stage and will do a "real" job of work, then you will have to wait till around 2010 when Peugeot releases their 307 (308?) diesel hybrid. It should deliver around 4L/100km.
Peugeot 307 Hybrid HDi - hybrid cars - TheGreenCarWebsite.co.uk blog

Press release documentation http://www.psa-peugeot-citroen.com/d...1138701208.pdf