[American perspective] In February I looked toward Euro bond markets as a safe haven for increasing Treasury yields, but the choices did not look good. For starters it appears to be impossible to even trade in foreign bonds with traditional brokerage accounts in the United States (hosted by E-trade, Morgan Stanley, Charles Schwab, etc).

Additionally, French bonds, while likely less-correlated with US Treasuries than other instruments, suffer from its own government having high debt levels; it's not a suitable safe-haven asset. Swiss and German bonds appear to be obvious alternatives. However, Swiss and German bonds' interest rates are low and in practice are little different than holding cash.

While gold appreciated in the short term, it is not simply inversely correlated with the value of the US Dollar. Its volatility is also driven by investors mitigating strict currency controls, mining productivity, and central bank activity. An unrelated downturn in one market could lead to a sell-off and wipe out gains. Gold also has no yield. Personally I think it's useful only in its physical form as a hedge for medium-term catastrophic events. Even then, a stockpile of food and clean water is likely far more valuable, if not substantially more difficult to store and maintain.

I ended up giving up, learning to love the S&P 500, and white-knuckling it ahead. Of the investable markets, the US one still generates the highest returns. (Chinese GDP growth is higher but its equities have low returns compared with other markets, due to political risk.)