Citro\u00ebn has pulled the covers off its Cactus concept model at the IAA 2013 Frankfurt Motor Show, revealing a car that lays the foundation for future C line models.\u00a0On introducing the new Cactus concept, designer Mark Lloyd highlighted one of the new features of the car by likening it to a smartphone. "When you get a new smartphone, the first thing you do is put it in a case," said Lloyd.That's what the Cactus's Airbump details are designed to do. Those grey inserts with green highlights are plastic elements designed to protect you from common scuffs and bashes that can be wiped away, rather than seeing you touching-up your paintwork.The Cactus is designed to be simple, stripping away the clutter and fuss from the interior. There's a low dash to make it feel spacious, as well as sofa-style seats, so there isn't a barrier between you and your passenger. Detailing is picked up in natural materials, with leather against contrasting grey which gives a homely, traditional, look.Of course this is a concept car, but some of the details that Citro\u00ebn\u00a0has chosen are interesting. The LED lighting picks up on the DS rear lamps that look to pass all the way through the car - it looks great and is really distinctive. On the inside the dials are replaced with two displays, one for the driver and one central retractable display.In introducing the Cactus, Citro\u00ebn\u00a0spent plenty of time talking about connectivity, that your car would have your music and so on, again, drawing on that smartphone reality of having everything available wherever you are.Under the hood is Citro\u00ebn's HybridAir system. This is a system in development that's designed to be more affordable than the battery-based hybrid system you'll find in the likes of the Toyota Prius. It still uses regenerative braking, but it compresses and stores air that can then be used for propulsion, in combination with the regular combustion engine.That should pin a fuel economy figure "in excess" of 94mpg", according to Citro\u00ebn, citing a 45 per cent reduction in fuel consumption when used in urban driving, when the HybridAir system will do most of the work.It's still a concept at the moment, but this could evolve into Citro\u00ebn's next C line car, bringing with it cheaper hybrid technology and a who load of tech.