I'm not aware of going prices, but if you want them, here are a few tips.
Right, air is sure going to be more expensive than sea.
Conventional (ie not containerized) sea freight is cheaper, but without the protection the container provides, I deem it too risky for the car.
Sharing a container with someone else's cargo will cost less (you'll only pay for YOUR car weight/volume, which will not fullfill the container by itself).
It's "mission : impossible" to comply with regulations/practices, customs and all, on your own.
So I recommend you enquire with several freight forwarders ("transitaires" in French) that deal with individuals, ask for their consolidation ("groupage") quotations.
Have them confirm by writting what they're going to take care of and what they're not, and pick the one that suits you best. Also check the international movers
It is particularly important that the one you choose be in a position to organize custom clearance and proper stuffing (putting the car in the box and have it properly secured and protected) at the point of origin.
Make sure you/someone you trust get a receipt ("packing list" or "Bill of Lading") acknowledging the car's condition and all fittings/accessories that are part of it upon being taken in charge by the forwarder or carrier there. It'll be too late when you see the car with this and that broken or missing if you've (most likely pre-)paid for transportation and don't have a B/L that explicitely states the car was in perfect (or better than upon arrival) condition.
And in any case you'd have a very hard time getting some compensation for damage.
Protect, or secure, or remove and ship separately, or put in a locked metal case EVERYTHING that's fragile and/or detachable. Have ALL those items (even the obvious like spare wheel, wheelcaps, mirrors, ... including above-mentionned parts case if any, body, exhaust, paint condition -- EVERYTHING) be shown on the packing list or B/L.
Some forwarders may offer delivery at Gennevilliers (Paris suburb), which may be of interest as you seem to be in Paris (otherwise, you'd have to go take your car at Le Havre...).
Be ready to be a --polite but insisting-- pain in the xxx to them : they can be nice people of course, but margins are slim in the transportation business, so they will seldom spend time explaining things to us Unknowing and Unsuspecting Fools Outside their Trade, and you risk ending up with many "and there's this additional cost, plus that tax, plus that fee..." and also "there's so much delay", as well as "Customs want this form" no one told you about, and also surprises like "the ship was diverted to that port" (900 Km from the scheduled one...) etc etc and the importing of the car of your dreams turns into a nightmare ...
OK,