"We're seeing a gradual reversal of the reforms that made Germany competitive," said Christian Schulz, from Berenberg Bank. "This won't be noticeable as long as Germany is in an upswing. It will hit in the next downturn."
Germany has outperformed EMU peers in recent years, partly due to a 20 per cent cost edge over Southern Europe caused by exchange rate distortions. It is also due to a boom supplying heavy goods for China's industrial leap forward, a phase that may not last as China shifts gears.
Jens Weidmann, the Bundesbank's chief, said the good years had masked underlying slippage, warning that Germany could become the sick man again if it was careless.
"An economic headstart can quickly be lost," he said. Investment has been falling and productivity has grown at just 0.6 per cent a year for a decade, half the OECD rate.
The BDI said the coalition deal failed to halt the surging cost of power under the country's Energiewende or switch to renewables. German firms pay twice as much for electricity as US rivals, and 30 per cent more than the EU average.
"The international competitiveness of German industry is in danger," said the BDI.
The deal will trim subsidies to solar and wind power to contain costs spiralling towards 1 trillion over 25 years, but at the same time it sets a renewable target of 55 per cent to 60 per cent of total energy by 2035.
This is much harder to achieve after Merkel's decision to wind down Germany's nuclear industry following Japan's Fukushima disaster.
The coalition ruled out any move on shale fracking. Utilities will have to rely on coal to plug gaps, playing havoc with Germany's greenhouse gas targets.
Cologne's Institute for Economic Research said the accord did little to prepare Germany for an ageing crunch, and watered down earlier plans to raise the retirement age to 67. Germany is already Europe's oldest society, with a median age of 45.
The deal offers no breakthrough on Europe, insisting on a "strict, sustained continuation" of EMU budget cuts.
"The principle that each member state is liable for its own obligations must be upheld," it said, vetoing any form of debt pooling.
"The agreement does not contain anything that would solve the European debt crisis, re-ignite growth in the euro periphery, or dampen the disastrous impact of austerity," said Sebastian Dullien from the European Council on Foreign Relations in Berlin.
"The message from Berlin to its euro partners is: the euro crisis is just not our priority. The economic problems you are experiencing are not our problems and we will not move until it becomes absolutely necessary."
