ELIZABETH JACKSON: The Bulldogs runaway player Sonny Bill Williams is now facing the prospect of criminal charges after defying an injunction and playing his first game for the French rugby union team of Toulon. 

But his rugby union career got off to a shaky start when he was sin binned for 10 minutes after a trademark shoulder charge. 

Williams walked out on a five year contract with the Canterbury club two weeks ago. And yesterday the Supreme Court made an order stopping him from playing for anyone else, which means he's now in contempt of court. 

Sonny Bill Williams was warned that if he ignored the order the court could seize his assets, including his million dollar mansion in Sydney's South.

Jayne Margetts spoke to sports law expert, Paul Horvarth.

PAUL HORVARTH: If the Sonny Bill incident can be seen to stand, then the Australian contracts are worth nothing, and you would think that it could expose the Australian league internationally to having all sorts of contracts simply disregarded by other international leagues.

JAYNE MARGETTS: What are the implications of Sonny Bill Williams playing in last night's game in France?

PAUL HORVARTH: Firstly is that it would be regarded as a contempt of court. That is that a court has made an order that he not play.

Secondly if he has any assets there, then potentially if the case were to go all the way, if the Bulldogs were to succeed against him, then those assets could be used in payment of damages for the breach of contract alleged by the Canterbury Bulldogs.

JAYNE MARGETTS: What are the chances of him ever being charged with contempt of court if stays out of the country?

PAUL HORVARTH: Well it's a good question. In my view couldn't be forced, or I'd be surprised if he could be forced to come back to the country. So he couldn't be extradited to Australia to face these court proceedings, being of a civil nature.

But in terms of contempt I'd be surprised if he's be extradited for that as well. So the net effect is by ignoring the court order he simply suffers potentially a financial loss, and it would cause him real difficulties were he to ever return to Australia.

JAYNE MARGETTS: Is this a test case in Australia? 

PAUL HORVARTH: Certainly, absolutely. It's got very broad implications across all sporting codes, because it raises the issue as to whether or not, what is the value of a sporting contract once it's signed with a professional sporting organisation. 

Clubs and individuals, the players, need to know that these contracts are enforceable and consequences will flow if people don't honour these contracts. 

JAYNE MARGETTS: These contracts are clearly not enforceable are they? If the worst that could happen to Sonny Bill Williams is that he would have his assets seized?

PAUL HORVARTH: The short answer is I think that's right. Unless there's some sort of international recognition, either in the courts or through international sports bodies, then I think that's right.

ELIZABETH JACKSON: Sports law expert, Paul Horvarth, speaking to Jayne Margetts.