GÜ insolvent - and now? (Payment plan etc.)

To assess the insolvency, I agree with 11ant. It is important that you under no circumstances pay more than has been installed. What is left unprocessed on the construction site can be reclaimed through retention of title. Go to the Bauherren-Schutzbund or a specialized lawyer and have the payment plan revised. Get an expert to check before payment whether a) the trade has been fully completed b) without defects.

I only hope that he continues to pay his craftsmen so that your construction can proceed.

Their money is secure for work after the insolvency filing if the insolvency administrator releases it. Money from before the insolvency application, even for services rendered, can be reclaimed. However, that is not the problem of the OP.

That is clear to me. But if his regular craftsmen are waiting for money for services rendered before insolvency (because they have to register claims), it can very well affect the business relationship and ongoing projects. And such things spread around in the industry. But the reason for the insolvency is probably known?

Honestly? There is no longer any presumption of trust in such a situation, I would immediately change the contract and adjust the payment terms in your favor. Otherwise, terminate. Do not provide liquidity out of your own pocket that only prolongs the issue. If necessary, have the books opened to you and confirm that the good man is really paying his bills with your money. Do not take the matter lightly just because the construction tycoon has an apparently plausible explanation – those guys can usually talk better than anything else...

Honestly? There is no longer any trust advance in such a situation, I would immediately change the contract and adjust the payment terms in your favor. Otherwise, terminate. Do not provide liquidity out of your own pocket that only prolongs the issue. If necessary, have the books disclosed to you and confirm that the good man is really paying his bills with your money. Do not take the matter lightly just because the construction magnate has a seemingly plausible explanation – these guys can usually talk better than anything else...

Is it possible to change the existing contracts?