D&D 5E How exactly does a Paladin break it's Oath?

[Maxperson]

I mean like technically and mechanically speaking. What if I'm an evil level 2 Paladin, and I want to take the Oath of the Crown because I feel like I could abuse it and/or gain power and profit from doing so. Is this possible, or restricted due to my "god" not allowing it?

This is up to the DM.

Could the Paladin break it's tenets when nobody is around to see and get away with it?

This is up to the DM, but I could consider the following. Tenets are not just some list of rules that the paladin gets from his god. The tenets of the oath are what the paladin gains his powers from.

"Some characters with this class don’t consider themselves true paladins until they have reached 3rd level and made this oath. For others, the actual swearing of the oath is a formality, an official stamp on what has always been true in the paladin’s heart."

You can see how important the oath and tenets are. Break them, even in private, and the DM can force you to stop being a paladin or take the oathbreaker paladin option.

 

[Maxperson]

So asking the DMs out there, would you allow a lawful evil Paladin to take an Oath or the Crown, Devotion, or Ancients? He'll behave accordingly in company at all times, but will probably "do evil things" in times he thinks he could get away with it. Obviously this character would have no qualms with lying, cheating, stealing, and killing if he thought he could get away with it. It would almost be like he was leading a double life. I just don't know if it would "work" like with the Pally powers and whatnot. I like for things to make a little of bit of sense and at least try to stay logical in decisions.

I would not. If you want to be evil, go with Vengeance or work with me to create a new oath.

 

[CTurbo]

We decided that the character could not start out as Oathbreaker, but the other 4 options were open and we would make it work. The random roll came up Vengeance so that should be easy. At level 4, we give a free random feat, and the evil Pally got Ritual Caster - Find Familiar so that is going to be interesting. We already decided the variant familiars are free game so the evil Vengeance Pally is going to have a quasit or imp familiar. Fun stuff.