To the left is a chart of the difference between interest rates charged Germany and France since late 2006. The higher the difference, the more worried investors are France will default, hence they will charge France a higher interest rate to borrow. To the right is a chart of Credit Default Swap (CDS) contract prices on major US commercial banks leading up to the 2008 financial crisis. The higher the price, the more worried investors were of US commercial bank default, hence the more willing they were to pay for CDS insurance contracts.
Notice a similarity?