A common approach would still work for China, if not Germany. Impute a value to acceptable standards of social and environmental services and costs, put a tariff equal to those costs on goods from countries that do not meet those standards. Rebate that tariff to those countries only for purposes that serve those ends. But, practically, the financial sectors of the US, UK, and the financial-industrial hegemons in Germany would have to be brought to heel and wealth distribution trends would have to be reversed for these policies to work.

Great minds think alike.  This is the way that I think it best to go to.  By placing a tax on the conditions of production, you avoid the issue of disparate treatment solely on the basis of country of origin.  The issue is the conditions of production, regardless of country.

A lot of the competitive advantage of the Chinese comes from externalizing costs, this would bring those back in.  

What we need is either a multilateral system that creates a common, basic standard.  Or a bilateral system that allows countries to have a tax that removes the advantage created by firms not being forced to produce products under conditions that reflect the legal regime where they are sold.

And I'll give my consent to any government that does not deny a man a living wage-Billy Bragg