There's probably some controversy about this....as it's even debated about why a California Common is called "Steam" beer. I would say just brew it the way you want to. If you want it fruitier, ferment it at 70 degrees. If you want it more lager like, ferment at colder temps.
I notice some yeast manufacturers call their California Common strains "ale" yeast and some call them "lager". IMO, the main distinction a California Common has from a lager is that it's lager ingredients brewed at higher temps. For what it's worth, my favorite California yeast is White Labs WLP001 California Ale Yeast. It also recommends fermenting at around 70...and I prefer these temps myself (I'm usually fermenting at 68 with a California Common). I notice that in order to get good results using lager yeasts in ale temps, those manufacturers that call theirs "lager" strains are rated towards the ale range...so there's really a gray area. Michael Jackson says that Anchor Steam ale is fermented anywhere between 60-72 degrees.