I once again warn you, do not just go by Citroen part number if you want to buy from a remanufacturer.
The picture posted by "Givemeabreak" shows 5271H8 which is indeed the correct part number for citroen. But do note that it shows a 52 bar pressure (presumably for non-hydractive, 2 front sphere configuration).
The link that you point to is Lizarte 20.00.0100 which is 44 bars (for a hydractive car, which needs a third central sphere). Although the reference number mentioned there is 5271.H8, it is incorrect. If you put these spheres, it will ride very hard!
The only way you can correctly check the Lizarte sphere for your car is through their own catalogue.
The correct Lizarte sphere for you car is 20.00.0103 (assuming that you have non hydractive (sport), with only 2 front spheres).
Please check once again if there is no third front sphere in your car (below your engine area). In your vehicle characteristics citroen profile for your car it says "ACTIVE SUSPENSION: MANUALLY ADJUSTED ACTIVE SUSPENSION", which is different from what it says for my C5: "ACTIVE SUSPENSION: WITHOUT HYDRACTIVE SUSPENSION".
In case you do find a third sphere, then you will need to buy all 3 spheres otherwise you will never get a soft ride.