It has proposed to extend the so-called 'cooling-off' period for Commissioners who leave office from 18 months to two years.
The cooling off period is the time during which a former Commissioner must inform the executive of his or her intention to engage in another occupation after leaving office.
For former Presidents the cooling off period will be extended to three years.
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The new rules come amid the ongoing row about former Commission President José Manuel Barroso moving to Goldman Sachs relatively soon after he left the Commission.
In addition to the extended cooling off period, Commission President Jean-Claude Juncker is also proposing that the rules which force Commissioners to step down from their functions when they want to run in elections to the European Parliament, is abolished.
This, he said, is on condition that it comes with "appropriate" safeguards to prevent the use of Commission staff or resources for campaign purposes.
The Commission also revealed that the ad-hoc ethics committee opinion on Barroso's move to investment bank Goldman Sachs is still under discussion.
Announcing the plans, Juncker said: "In the future, like it is common practice in all our member states, I want the members of the Commission to be able to stand as candidates in European elections without having to step down from their tasks, as is currently required by the framework agreement.
"European Parliament elections are and should be a necessary rendez-vous with democracy, also for the Commission."
He added, "At the same time, in the light of recent experience made with members of the previous Commission, I feel that our code of conduct should be tightened in order to set the highest ethical standard possible for possible cases of conflict of interest."
However, the new rules have met with lukewarm response from transparency campaigners.
According to the Alliance for Lobbying Transparency and Ethics Regulation (ALTER-EU) the rules will still fail to prevent future ethics scandals.
Corporate Europe Observatory's transparency and ethics campaigner Margarida Silva said, "The suggested tweaks to ethics rules for ex-Commissioners are nothing but a band-aid - they cannot patch over the many holes in the code of conduct.
"Despite numerous scandals in the past months, President Juncker is apparently still reluctant to recognise the full extent of the Commission's ethics problem.
"A slight change to the ethics rules will also not save the European Commission's face right now. It does nothing to address the Brussels culture that approves of Commissioners, officials and MEPs passing into corporate jobs burdened by conflicts of interest.
"By refusing to create a stronger ethics body with fully independent members and the power to investigate breaches of rules and to impose sanctions, Juncker continues to allow Commissioners to regulate themselves. This means we are likely to see more revolving door scandals of the sort linked to Barroso or ex-Commissioners Neelie Kroes and Karel de Gucht."
Further reaction came from Friends of the Earth Europe campaigner Myriam Douo, who said, "It has been more than four months since Barroso joined Goldman Sachs, and the ethics committee already published its recommendation over three weeks ago.
"But the Commission has still not made a decision. Instead of procrastinating when there are allegations of unethical conduct against Commission officials, Juncker should take these cases seriously and act swiftly.
"More important still, a proper ethics system has to stop Commissioners acting as judge and jury towards their colleagues and pass this power over to an independent and transparent ethics body."