The German FA (DFB) has reacted to Dortmund's warning that the city could withdraw its bid to become a host at the 2024 European Championship by inviting city representatives to hold talks.
It has also moved the deadline for cities to make their host applications formal back by a month from the original date of June 12.
On Wednesday, the mayor of Dortmund warned that the city could withdraw its bid to become a host because of an unclear financial situation.
Local outlet Reviersport quoted Ullrich Sierau as saying: "If the business model of the German FA and UEFA is to let us pay and them cash in, then it's a bit lopsided."
Sierau said the DFB demands that candidate cities "support them in the best way at their own expense," adding that it could not accurately be estimated how high those costs might be.
Reviersport said the bill facing the city could hit €30 million, and earlier this month Kaiserslautern announced it had withdrawn its bid because of "irresponsible financial risk."
On Thursday, the dpa news agency reported that the DFB had pushed back the application deadline for candidate cities to July and invited representatives to talks, set to take place on June 7.
It quoted Sierau as saying: "It's apparent that our efforts were successful."
Germany and Turkey will compete to host the 2024 tournament, as they are the only nations to declare an interest. UEFA's executive committee will make a decision in September 2018.
With Germany considered to be the favourite, 14 cities have so far announced that they will bid to stage games.