Currently, Paladins are only known in Espera. They Detect and Smite Arcane rather than evil.
For the purposes of Detection, an arcane caster will have an aura identical to that of a cleric of an evil deity, on the Detect Alignment chart (CRB 266). Creatures summoned, called, conjured or otherwise manifested through arcane magic will have an aura equivalent to an evil outsider. Otherwise, the ability will function as Detect Magic, though it will only identify arcane magics.
The Smite Arcane ability can effect arcane casters, summons, as well as any creature, character or object currently affected by an arcane spell or ability. A 6th or higher level paladin can also use a smite to break an arcane spell, the same way a barbarian with the Spell Sunder rage power can..
A Paladin’s code of conduct prohibits them from utilizing arcane magic, permitting arcane magic to be used on them (a failed save does not constitute a violation. Permitting a wizard to cast a spell on her does). They must act with honor, still, and must punish those who use arcane magic. A paladin may ally with an arcane being under exceptional circumstances, to defeat a greater arcane being, but any long-term association of this sort will result in their losing all class features.
In all relevant situations, any spell or effect created by any creature summoned by divine magic is considered divine, and any spell or effect used by an arcane creature summons is considered arcane.