Here are 4 tips for today's trading. This will help you decide where you should invest and what to look for:
1. Paris in mourning
The Euronext Paris stock exchange opened this morning with added security measures in place. The key Parisian index -- the CAC 40 -- initially dropped by about 1% but then recovered and was little changed in late morning.
Most other European stock markets were narrowly positive, reversing early losses.
But European airline and tourism companies are taking a big hit as investors worry that the Paris attacks will scare people away. Shares in the parent company of Air France are dropping by about 5%. Shares in the French hotel group Accor (ACCYY) are also declining by about 5%.
The euro is also declining against all major global currencies, including the U.S. dollar. It's currently trading around $1.07.