I can't think of any such international examples. But also, it's not so much the central government that acts at that level, but a range of actors, which include investors, SOES, private companies, contractors and service providers. And then there's the fact that international "rules" in environment (and to some degree also labor) are more norms than rules, often with weak enforceability. The research I've done on Chinese overseas engagements (in agriculture, hydropower, forestry, extractives) tells me that reforms in labor practices over the past 10-20 years have also emerged organically in the way they did (and continue to do so) within China--that is, as you say, because improving labor (and sometimes environment) practices of overseas operations proved less costly than not.

And yes, absolutely the experience of environmental improvements in China has shown the power of social mobilisation at the grassroots level, but this has changed a lot in recent years with Xi taking tighter control. As my colleagues in environmental civil society in China have explained, ironically, as China has strengthened its environmental governance (created MEE, established better laws, improved coordination among government bodies, etc.) in recent years, this has actually shrunk the space for civil society. Judith Shapiro and Li Yifei have an excellent discussion of this in their recent book on Coercive Environmentalism https://www.wiley.com/en-us/China+Goes+Green%3A+Coercive+Environmentalism+for+a+Troubled+Planet-p-9781509543113