PARIS — France and Germany today called for a “new economic government” for Europe, with mandatory balanced budgets enshrined in the constitutions of all eurozone members as a way to overcome the debt crisis that has threatened to fracture the continent’s fragile common currency.

French President Nicolas Sarkozy and German Chancellor Angela Merkel’s push for long-term political solutions instead of immediate financial measures like a single European bond sent the euro sliding.

Sarkozy and Merkel also proposed a Europe-wide tax on financial transactions and pledged to harmonize their countries’ corporate taxes in a move aimed at showing the eurozone’s largest members are “marching in lockstep” to protect the euro.

Shares of financial markets operators, such as NYSE Euronext and the IntercontinentalExchange Inc., already under pressure as part of a broader sell-off of financial stocks, tumbled.

NYSE Euronext fell 10 percent, or $2.87, to $26.10, leading the S&P 500 Index in percentage losses. The IntercontinentalExchange was not far behind, falling 5.5 percent, or $6.33, to $110.10, the third biggest loser on the S&P.

Investors may be concerned about how the euro bloc will put in place what its leaders have suggested and how a proposed tax on financial transactions may affect demand for European assets, said David Gilmore of Foreign Exchange Analytics in Essex, Conn.

By The Associated Press