The Center for American Progress has proposed setting the minimum wage at half the average wage (mean, not median as used above) for production and non-supervisory workers; at the current level, that means a $10.07 minimum. If we were to adopt France's 60 percent ratio, that'd put us at about $12.08.
Of course, there are all kinds of pros and cons to that kind of increase. I went through many of them here. And it's worth noting that Australia's minimum wage comes with all kinds of exceptions, especially for younger workers.
Update: Another point, which Guan Yang reminded me of on Twitter - a large number of countries, including Denmark, Germany, Italy, Norway, Singapore, Sweden, and Switzerland, don't have minimum wages at all. Most of them make up for it with widespread collective bargaining, which sets de facto minimums.