Hi
I sat for the eTEF (Test d'evaluation de Francais) in Montreal.
By the time I was allowed to apply for citizenship, the Harper government enforced the language requirements rules and we had to provide solid proof, this creatid a jam and test sittings rush.. as the eTEF was faster to book a seat for than the english CELPIP (1 week to sit in Montreal back then vs 3 month for the CELPIP ) , I booked it and went for the test than to know to my surprise that it would take at least 4 weeks for France to assess and respond with a certificate! and 6-8 week on average
Since I had to apply sooner than later as the backlog was growing on average by 2 month for every 1 month delay by then.. I found a seat for the CELPIP in Halifax that was 2 weeks away and the results would be immediate.. thanks to my Aircanada miles I flew there for the test and back the same day and applied back in September 2013. The TEF results came in a few weeks later. and the application was returned regardless for Kids school certificates copies (that were not mentioned in the application as I was not applying for them.. then I knew they had a trend to reject applications for any reasons in order to streamline the statistics..)
Whatever.. below are the links for the TEF and CELPIP
http://www.francais.cci-paris-idf.fr/tef-et-etef/
http://www.celpiptest.ca/
For the experience, I would say the TEF is more demanding and involves human interaction with testers.. while the CELPIP was fully a computer based test.
For the French there were 2 parts, a discussion plus expression dialogue and a sitting over the computer test for reading and listening + comprehension.
I do not recall all the details, but bottom line it is to assess your levels of fluency, thus you do not need to prepare at all..
For the English test the funny part that there was a family of Scottish immigrants passing the test.. as the law is the law and they had to provide a letter stating they can speak English