Article is devoted to S. P. Trubetzkoy's exposure to French political life and revolt of Riego 1820 during travel of the Decembrist to Paris. The influence of these events on folding of political developments of S. P. Trubetzkoy and preparation of revolt on December 14, 1825 is shown. The beginning of development of the Constitution by N.M. Muravyev and the plan of its use suggest that the idea of a revolt with a scenario similar to development of Riego's promusamiento began to form gradually in ideology of Decembrists. In 1825, during an interregnum, S. P. Trubetzkoy will offer the plan which reproduces basic elements of the Spanish mutiny of 1820. Thus, it is possible to draw a conclusion that the Spanish events became a "hint" for Decembrists - they prompted the scenario of implementation of their political program. Refs 29.