By Martha Graybow

NEW YORK, April 3 (Reuters) - JPMorgan Chase & Co (JPM.N: Quote, Profile, Research) has sued Dutch businessman Louis Reijtenbagh, saying he failed to pay back more than $23 million in loans and that he unlawfully moved valuable artwork by Rembrandt, Picasso and other artists out of the United States that had been put up as collateral.

The case is the second lawsuit in two weeks against the 62-year-old Reijtenbagh, a one-time medical doctor who is now considered one of the wealthiest people in the Netherlands after making a fortune through investing.

Reijtenbagh and his two sons were sued last week by Credit Suisse Group AG (CSGN.VX: Quote, Profile, Research), which has gotten a temporary court order freezing his assets. [ID:nnN31305455] Several investment funds run by the Swiss bank accuse them of misusing more than $340 million in loans that were to have been used to finance the family's private equity investments.

The Credit Suisse and JPMorgan cases were both filed in New York State Supreme Court in Manhattan.

The JPMorgan lawsuit, filed on Wednesday, seeks the repayment of loans that were backed by millions of dollars worth of artwork held by Monte-Carlo Art SA, a British Virgin Islands-based entity that JPMorgan says is controlled by Reijtenbagh.

Jay Fialkoff, a lawyer representing Reijtenbagh and his sons in the Credit Suisse case, told Reuters on Friday that he was "not sure" if he was going to represent the investor in the JPMorgan lawsuit and declined to comment on it.

A hearing in the JPMorgan case has been set for April 15, according to court documents.

The Reijtenbaghs have been described in court papers as a wealthy Dutch family with offices and residences in Brussels, Monaco, Luxembourg and New York.