I could swear it was the same as the master , but i also cant find it.
Well , i would keep it that way to avoid obvious conflict , since the familiar is nothing more than the extension of the PC , it would be weird if they could disagree or something.
I've always ruled that the familiar shares its master's alignment but something you just said made me think -- "to avoid obvious conflict" -- if your caster/master were CE or NE, their nature is to be selfish and self-serving above all else. Therefore, if your familiar matches your alignment, then THEY would be selfish and self-serving. Imagine a familiar which would throw its master under the bus to save its own neck, or even just because it produced some short term need or desire - like food or extra loot. Or maybe even just if it thought it was funny. In my mind, a CE or NE underling is going to be treacherous by nature.