Possibly a pipe to/from turbo or intercooler loose or split.
http://www.honestjohn.co.uk/forum/post/index.htm?t=46211
http://www.frenchcarforum.co.uk/forum/viewtopic.php?t=45075
https://uk.answers.yahoo.com/question/index?qid=20131014092109AA2ajBz
Loads of other search results for "citroen dispatch turbo smoking"
You DID try a search for yourself first, didn't you?
February 2016