My kids are also in French immersion and I chose that over homeschooling. I would consider talking to the teachers and seeing what they feel is important to them in a classroom environment. The teachers have a core curriculum and can be very reading, writing, and arithmetic oriented or they can spin teaching in their own flare using very creative methods. In the 8 years that my kids have been going to school the only terrible year that I had was last year and over the summer I considered keeping them home again. I knew the teachers going into this year where great and decided to stick through it. I don't think that this Elementary school is at the top of the standardized testing and according to a school board dad who's daughter was in the same grade as mine, was so disgruntled with the school he changed schools. He was an educator at a university and had these super high expectations. But I see the good stuff within the school that does not show up on standardized testing as I volunteer several times a week. They have an amazing music program with a music room filled with 40-50 instruments and plenty of students that have won provincial medals, their school plays are phenomenal that they could be performed in Hollywood or Broadway! Honestly! (the art/drama teacher is amazing) , they have huge parental support and great school spirit, character trait recognition program and many more things I could list.
My dd2 was harmed by a teacher last year that she was to take this standardized test from the start in September when the test was the last week in May. They did everyday drills, got yelled at and the pressure and anxiety was so overwhelming. She was slow to pick up on French and that added to it.
However, I feel it is important for my kids to learn a second language. Real life is not all about test scores, but more importantly how you communicate and connect to people in their language. IRL you can have the best product on the market but if you can't communicate to your customer base why they need it .. the sales will be flat. My sister is a Veterinary Dr. in a border town to Quebec. She does not speak french when the majority of her clientele are bilingual and some of them can't speak English. Even though she has the brains she can't diagnose problems or give medical instructions to those clients and has to take extra time for translations. Time = money in her practice because the less clients she sees then less money comes in.