In this answer, @Will mentions:
Believing in the Sith Religion and philosophy is legal. However, using an offensive and lethal weapon (lightsaber) without being authorized to since only Jedi are authorized to use lightsaber a just as in some countries you need gun license....
Was it actually illegal in the Republic for a non-Jedi to own, possess, or use a lightsaber? I'm asking about cases where blasters or other weapons were permitted - e.g. in a case where non-Jedis carrying personal defense blasters was perfectly legal, would it have been legal instead for someone to strap a lightsaber on their belt as long as the lightsaber itself wasn't stolen (a la General Grievous) or built from stolen parts? Were all lightsabers legally considered property of the Jedi Order with no exceptions? Was there a civilian permitting process that was more intensive to that required for blasters? Was there an actual "Aggravated possession of a lightsaber by a non-Jedi" statutory offense?
To be clear, there's quite a bit of evidence that the Jedi Order attempted to restrict access to lightsaber crystals (via concealing mines, etc.), so it's possible that 95%+ of lightsabers that a typical non-Jedi might find in the marketplace would be stolen or built using a stolen crystal, and that possessors of such lightsabers would (if caught) be charged with Possession of Stolen Property or a similar offense, but is that all, or were the 5% or less of "legit" lightsabers also unlawful to possess? In other words, was this more of a "The Jedi have manipulated resources and the economy to make it really really hard for anyone else to acquire a lightsaber" or a "It is a Class 5 Felony for any non-Jedi to possess a lightsaber, punishable with up to 5 Standard Years of imprisonment, or, for a second offense, execution by Rancor Pit"?
If the legality of this depended on planet (e.g. it was 100% legal on Corellia, 100% illegal on Coruscant, and legal on Naboo only for persons over 21 who could pass a literacy test and had fewer than two felony convictions), that's an answer.