Please go to this guide on the CIC website.
http://www.cic.gc.ca/english/pdf/kits/guides/EG7.pdf
It is clearly stated on page 10 that TEF is the only test which is acceptable for French language proficiency.
The test procedure for TEF and DELF is different.
In DELF you sit the test which you feel is your proficiency level. For eg if you are a beginner you'll sit in A1 or A2 level, moderate in B1 or B2.
In TEF everyone sits the same exam and based on your score your proficiency is decided.
DELF is valid for Quebec Immigration, but not for FSW.
It is similiar to TOEFL and IELTS. Even in IELTS we need to give only general module.
Hence anyone wishing to take points for French language skills for FSW need to give TEF.