Reuters writes about this with reference to a European official.

According to him, if a decision is made on confiscation, Russia may file lawsuits and begin confiscating Euroclear funds in other countries. 

“There is a risk that Russia could seek legal action to seize Euroclear funds held in securities depositories in Hong Kong, Dubai and elsewhere.

The concern is that this could deplete Euroclear's capital and require a huge bailout.

It is assumed that even in the event of a decision to confiscate Russian funds, the Belgian system will have to retain some of this money as insurance against Russian retaliation and avoiding bankruptcy.

Earlier, the leader of the French Patriots party and candidate for the EP elections, politician Florian Philippot, said that the use of frozen Russian assets in the European Union is illegal and stupid.