Thank you and @dodogirl for the replies. This is what I wanted to know, what is the break-up of maximum points which can be obtained through French as second language. I understand it'll be extremely difficult to go beyond CLB5 (or even to reach that), but at least good to know the maximum possible target!This is correct. If you get at least CLB7 in all four abilities, you may add 30 points.
In 2016, when I first thought about immigration to Canada and sought help from a colleague who already got PR, he did my possible CRS calculation by assuming CLB9 in IELTS and it was well below cut-off. In 2017, I didn't even look into it. When I started the process again this year, I realized that CLB 10 can give 12 additional points over CLB9, and I scored it in first attempt! So, lesson learnt: always know the maximum achievement possible before starting any process