The IMF managing director, who spoke with CNBC from the organization's headquarters in Washington, said she had not been warned about the move ahead of time, which she found "a bit surprising."
Still, she said it was possible that Thomas Jordan, chairman of the Swiss National Bank's governing board, may have reached out to someone else at the IMF.
She said she would "reserve judgment on the pertinence of the move" until she discusses it further with Jordan.
The Swiss franc rose nearly 30 percent against the euro after the announcement. The move comes ahead of a European Central Bank meeting next week, in which the ECB is expected to announce monetary stimulus measures.
Lagarde predicted that "we will see more volatility" of capital flows and exchange rate currencies as different central banks pursue "asynchronous" policies.
Weighing in on the Federal Reserve' s signaling that it would likely raise interest rates in 2015, Lagarde said she expects that "they will do a fine job at really looking into all of [their various indicators] and making the right decision at the right time."
There will be a year of the Fed raising rates, she said, because "the U.S. economy is clearly doing well and is currently a big engine for growth."
The rest of the world, however, may not have such a rosy economic outlook, she said. Europe-with the exception of the U.K.-"is still low, fragile, and it needs to be much stronger, cohesive, more balanced, and structural reforms are going to be absolutely needed-strongly," she said.
Despite these problems, Lagarde said she did not see a Greek exit from the euro zone on the horizon.
Lagarde said in a speech earlier on Thursday that the IMF sees "the global recovery continuing to face a very strong headwind" despite cheaper oil and strong U.S. growth.
She said the world economy will face three major policy challenges over the next year: boosting growth and employment, achieving inclusive and shared growth through structural reform, and attaining sustainable and balanced growth.
The IMF cut its global growth outlook in October.