Worrying might be a touch too extreme, but there's no question that the slowdown in once-booming Chinese car sales is starting to cause furrowed brows among car makers ahead of the Geneva motor show.

The slowdown - most notably among premium brands - actually translates as 5-10% year-on-year growth, but when you've been used to a diet of upwards of 30% growth for the past few years, and invested hundreds of millions in building factories to sustain that growth, you can understand the concern that is now being expressed.

The reasons are many and varied, but it's clear that Chinese government legislation is at least partly to blame. The major cities are clamping down on second car ownership in order to combat pollution and congestion, for instance, while infrastructure and prosperity in second and third-tier cities is inevitably of a smaller magnitude.