Forty-two members of Congress have submitted a Section 301 petition in relation to Chinese and Japanese currency valuation. According to the press release:
The petition, filed under section 301 of the Trade Act of 1974, calls on the United States Trade Representative to take strong action to end China’s continued undervaluation of its currency, the renminbi (RMB), and to consider taking action against the undervalued Japanese yen.
Here are links to the summary portion of the petition and an "accompanying letter." I'm not sure where the full petition can be found. The summary says that the RMB undervaluation is a "prohibited export subsidy" and says that it "frustrates the intent of and breaches basic principles of" the GATT. The summary also refers to Articles IV and VIII of the IMF's Articles of Agreement.
Previous petitions have been rejected by USTR. We'll see how this one does. The article notes:
Since prior rejections of the "Section 301" petitions, however, the Democrats have gained control of Congress and the White House needs their cooperation on a long list of trade priorities, including renewal of trade promotion authority to negotiate trade deals.