Click on the "Live Audio" icon near along the left-hand side of the page. Paris is 6 hours ahead of the USA East Coast during this time of year, so make sure you adjust for that in order to get the correct audio feed.
Also, you can get the live text update through www.eurosport.com
, but better yet, I'd goto the IAAF website, click on the 9th IAAF WC icon (just under "Live Now" along the right-hand side of the page. From there, you can click on the icon "Select your channel" under the General Info section on the right-hand side of the page. You'll be able to see the full text read-out of the competition as it happens.
Here's some general info. "Live Audio" is actually delayed by about 10 seconds across the web, so if you are listening to the audio and watching the text update as it happens, you'll see the result on text prior to hearing the result on audio.
Hope this helps.