Call Motorcycle Express, or look at their website. That is the easiest, fastest, and simplest way of moving a motorcycle across the Atlantic.
The very cheapest way would be to ride it to Paris and air-freight it from Paris to Canada (either Toronto or Montreal), then ride the darn thing across the continent to California. The next cheapest way would be to ship it as far west in Canada as you can, then ride south from there.
Once you start shipping into the United States, the price goes up quite a bit. This has to do with the availability of a large amount of cubic space but only a small amount of weight capacity (the perfect formula for cheap motorcycle shipping by air) on Air Transat, a large charter carrier who fly from Europe to points in Canada.