A regional regulator said it had raised some objections to exchange operator Deutsche Boerse's
There are legal reservations about the deal, the Hessian Ministry of Economics said in an e-mailed statement on Monday.
The ministry, based in Wiesbaden, Germany, has the power to revoke Deutsche Boerse's operating licence, a key prerequisite to a successful deal.
The ministry said it had submitted a list of suggested amendments to the deal, but had not received any answers from Frankfurt-based Deutsche Boerse.
The merger partners now need to make appropriate proposals about how to address the reservations, Ulrike Franz-Stoecker said in an e-mailed statement.
The ministry declined to provide details about the list of objections.
The Hessian ministry has in the past said it would give its final verdict on the takeover after antitrust authorities in Brussels had ruled on the deal.
Deutsche Boerse said on Monday it was in constant dialogue with the Hessian supervisor.
The deal has met with intense scrutiny from the European Union.
The merger partners could spin off parts of their derivatives arms to create a third-party competitor as a way to allay antitrust concerns about their $9 billion merger, sources have said.
(Reporting By Andreas Kroener; writing by Edward Taylor)