Magic: The Gathering - Are there behavioral rules for sanctioned MTG games?
Yes, there are behavioural rules, and yes there are consequences.

Chapter 5 of Wizards official tournament rules outlines Unsporting conduct.


  5.2. Unsporting Conduct — Major
  
  Penalty: Game Loss
  
  Definition
  
  Unsporting Conduct — Major infractions fall into three categories:
  
  
  Failing to follow a direct instruction from a tournament official.
  Insulting another person based on his or her race, color, religion, national origin, age, gender, disability, or sexual orientation.
  Aggressive or violent behavior that is not directed at another person or another person’s property.
  
  
  Examples


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  D. After losing a match, a player throws his cards onto the table and knocks his chair over in anger.


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  Additional Remedy
  
  The player must correct the behavior immediately, and can expect to be removed from the tournament venue upon further offenses. As with Unsporting Conduct — Minor infractions, if the offense occurs at the end of a game, it is acceptable for the judge to apply the penalty to the next game instead.


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  5.5. Unsporting Conduct — Aggressive Behavior
  
  Penalty: Disqualification
  
  Definition
  
  A player acts in a threatening way towards others or their property.
  
  Examples


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  D. A player tears up a card belonging to another player.
  
  E. A player intentionally turns over a table.
  
  Philosophy
  
  The safety of all people at a tournament is of paramount importance. There will be no tolerance of physical abuse or intimidation.
  
  Additional Remedy
  
  The offender should be asked to leave the venue by the organizer.


Depending on the ruling of the judge, your opponent could either be disqualified or assessed a game loss. I believe in this case, if he touched your cards and threw them on the floor, that would fall under 5.5 and he should be disqualified.

Edit:

AHA, just noticed you asked about REL events. Well this is what the Judging at Regular REL document has to say:


  There are also certain behaviours that will not be tolerated in any event. Any player engaging in the following must be disqualified from your event;
  
  
  Aggressive, violent or abusive behaviour (physical or verbal)
  Cheating, lying or intentionally making illegal game actions or trying to avoid penalties
  Influencing Match outcomes (by incentives, coercion or random methods)
  Theft (this includes things like replacing a chase rare in a draft with one from their binder)
  
  
  If you do have to hand out a Disqualification, let the players know that while your decision is final, the DCI would still like to hear their side of the story. Contact your WPN representative directly, and they will advise you further.


So they tournament organizers would be well within their rights to disqualify this person for aggressive behaviour, but they have more leeway. In any case, it certainly is grounds to call over a judge.