Lufthansa and SWISS are currently offering a fantastic fare for travel from Paris to California in Business Class. In looking over valid travel dates, it appears that the fares are available into early next year. However, it looks like the fares are valid for travel on Monday / Tuesday / Wednesday. Going into 2018, the fare seems to only work for Monday travel. Regardless, you can book a roundtrip ticket for only $1993.
Since this is not an advertised sale, I don’t know how long the fare will last, or if in fact it is an error fare which can be removed at any time.
As with any fare published by Lufthansa, the same pricing would apply to flights operated by other Star Alliance carriers that flight the same route.