UPDATE 2-Maryland seeks review of Constellation/EdF deal

* Maryland says must approve Constellation/EdF deal

* Constellation says to appeal state ruling (Adds EdF comment, 5th paragraph; stock down)

NEW YORK, June 11 (Reuters) - Maryland regulators ruled on Thursday that power company Constellation Energy Group Inc (CEG.N) must receive state approval for its planned sale of a stake in its nuclear unit to Electricite de France (EDF.PA).

Constellation, which suffered a liquidity crisis last year, had hoped to avoid the approval process in the state because EdF is only buying a minority stake in the utility's nuclear business.

But the Maryland Public Service Commission ruled that the French power company would be acquiring "substantial influence" over Constellation's utility, Baltimore Gas & Electric, making it subject to commission authority. The commission also said it has reached no conclusions about whether the transaction should proceed.

Constellation said it will appeal the ruling, but it expects EdF will file for approval for the deal with the Maryland Public Service Commission.

A spokesman for EDF said: "Although we disagree with the Commission's decision, we will continue to work towards completing this transaction so that these benefits can be achieved."

Constellation had agreed to sell nearly half its nuclear power business to EdF for $4.5 billion, breaking up a takeover of the company by Warren Buffett's MidAmerican Energy Holdings. At the time, EdF was already Constellation's biggest shareholder.

"We strongly disagree with the commission's conclusion that EdF's less than 50 percent investment in our nuclear subsidiary would result in EdF acquiring the power to exercise substantial influence over our utility, BGE," Constellation Chief Executive Mayo Shattuck said in a statement.

Constellation has previously had a planned deal collapse due to regulatory concerns in Maryland. Florida power company FPL Group Inc (FPL.N) scrapped a $12.5 billion takeover of Constellation in 2006 after the merger became embroiled in state politics.

Constellation shares fell 6 cents to close at $26.96 on the New York Stock Exchange. (Reporting by Matt Daily and Michael Erman, editing by Gerald E. McCormick, Richard Chang)