[None][1] already explain the technical and etymological difference.

The main difference is that in European French, or at least in France, *chandelle* is mostly used nowadays in set expressions, some of them already mentioned earlier in comments:

- *brûler la chandelle par les deux bouts*: to burn the candle at both ends  
- *voir trente-six chandelles*: to see stars, to be knocked out   
- *dîner aux chandelles*: romantic dinner    
- *tenir la chandelle*: "to hold the candle", to be a third wheel
- *devoir une fière chandelle*: to owe a great deal to someone.  
- *le jeu n'en veut pas la chandelle*: something doesn't worth the effort   
- *économies de bouts de chandelle*: penny-pinching savings 
- *monter en chandelle/descendre en chandelle*: to zoom (plane)  
- *faire une chandelle*: to lob (e.g. tennis)  

As you can see, there are plenty of such idioms so the word itself is well alive, despite being almost unused alone.

The derived words *chandelier*/*candelabre* are also mostly used for antiques and substituted by *bougeoir* for current candle holders.

There is also a third word, *cierge*, specialized for candles to be lit in a church.

Canadian French kept *[chandelle][2]* as its main word for candle and mostly reserves *bougies* for [spark plugs][3]. That means in Québec, you would more likely hear *souffler ses chandelles* while in France, that would be *souffler ses bougies*. Both expressions are of course understood everywhere. 


  [1]: https://french.stackexchange.com/a/47005/1109
  [2]: http://bdl.oqlf.gouv.qc.ca/bdl/gabarit_bdl.asp?t1=1&id=4009
  [3]: https://french.stackexchange.com/questions/47004/whats-the-difference-between-bougie-and-chandelle-in-french#comment95206_47005