The Commission will define "social limits that cannot be adjusted downwards", and bring more consistency to the "world of work in Europe", Juncker said in a speech to a European trades union meeting in Paris (link in French).
This will include standard levels of pay across Europe. "We must finally agree on a simple principle: the same pay for the same job wherever it is," Juncker said.
Workers need the security of permanent employment contracts, Juncker said. Short term and fixed contracts are becoming normalised, he said, and this must change.
"My father was a worker in the steel industry," Juncker said. "If he had had to live in fear of not having his contract renewed every six months, I would not have been able to go on to [study law]. Modest people with few resources need predictability," he said.
The economic and monetary union of the European Union will need to be deepened, Junker said, in order for this to take place.
Juncker also described an "enormous gulf" between Europe and its citizens that needs to be resolved. "The citizens have become distanced from Europe because Europe has become distanced from them," he said. Social dialogue must be improved, and he encouraged trade unions to be part of re-starting that conversation.
Earlier this month, French prime minister Manuel Valls told a press conference in Paris that he supported a report recommending that more employment rules should be created through negotiations between unions and employers, rather than by central policy. The French government plans to scale back the country's employment laws by early next year as part of plans to boost growth.