Don't think so since EU laws regarding the single market of financial services make any renationalisation illegal...it doesn't make any sense, nonetheless it doesn't allow fraud.
All that shouldn't be a distraction from the core of the problems the French economy faces after the  last Markit published set of numbers placing France Manufacturing PMI just ahead of Greece but behind everybody else....

Germany 49.0  2-month low
Ireland 48.6  14-month low
Austria 48.1  3-month low
Netherlands 48.0  10-month low
Italy 44.5  7-month low
Spain 44.2  5-month low
France 44.0  3-month high
Greece 42.1  2-month low
http://www.markiteconomics.com/MarkitFiles/Pages/ViewPressRelease.aspx?ID=10921
http://www.markiteconomics.com/MarkitFiles/Pages/ViewPressRelease.aspx?ID=10903
Mr Cahuzac can be a side show if French politics truly require some excitement but the urgency is elsewhere, retail numbers published on March the 28th (http://www.markiteconomics.com/MarkitFiles/Pages/ViewPressRelease.aspx?ID=10891) were dreadful just before a disastrous manufacturing and tomorrow morning the composite PMI isn't expected to en-light the immediate future to be mild.
A response to these major challenges to the economy can't wait.....