Speaking of which, Thomas Piketty has been making the rounds, presenting his proposal for a "coalition of the willing" for issuing joint debt, something that has been opposed by the "frugals" in the latest EU Council meetings. This could start by joint issuing between, say, Portugal, Spain, France and Italy.

More details (in English) in Politico.eu:

Thomas Piketty: Willing EU countries should spearhead fiscal union

He also said that opposition from Germany and the Netherlands should not discourage France, Italy and Spain from issuing joint debt, known as eurobonds or corona bonds, as a way to tackle the fallout from the coronavirus crisis.

"It is perfectly possible for two countries, or three and four countries -- France, Italy, Spain -- to create corona bonds," Piketty said about European answers to the crisis, and thus "mutualize interest [rates]."
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Asked whether such a multispeed approach would not risk a break-up of the eurozone, Piketty said Europe had more to fear from rocketing interest rates in countries such as Italy -- which threatened to delay the recovery and propel the EU into another debt crisis -- than from asymmetrical fiscal or political integration.