"No Title of Nobility shall be granted by the United States: And no Person holding any Office of Profit or Trust under them, shall, without the Consent of the Congress, accept of any present, Emolument, Office, or Title, of any kind whatever, from any King, Prince, or foreign State." ARTICLE I, SECTION 9, CLAUSE 8

Emolument
The profit arising from office, employment, or labor; that which is received as a compensation for services, or which is annexed to the possession of office as salary, fees, and perquisites. Any perquisite, advantage, profit, or gain arising from the possession of an office.

Trump is not in the employment of any foreign state. 

Washington was a planter, in the export business. Merely having business dealings with foreigners isn't enough.

In any case, the proper venue for any such charge is the House, where articles of impeachment can be brought. Some random inferior judge doesn't have jurisdiction.