Car stolen, how to negotiate with insurer

[Parisien]

First time this has ever happened, how do I proceed, it was a sporty SUV, just 3 years old , less than ten thousand miles, a couple a grand of extras.

Currently can't find one in that spec,engine size and year, especially for amount offered, about 4 or 4.5 k under nearest equivalent cars, albeit a year younger as none of that year on the market.

Any help appreciated