The Vincentiana Collection at DePaul University recently purchased this very early holy card depicting a scene from the life of Rosalie Rendu. This incident took place during the revolution of 1848. Sr. Louise Sullivan has an account in her biography of Rosalie on pages 179-180. The card does not name Sr. Rosalie, but it depicts her historical role in this incident. The card certainly dates to within years of the event. The back of the card has this description (translated from the French).
"It is in times of trials and terror that the sublimity of religion is clearly revealed in the devotion of its ministers and its virgins. While in the faubourg Saint-Antoine the venerable prelate of the capital (Msgr. Affre the archbishop) gave his life for his sheep, in the Saint-Marceau district an officer of the national guard was saved by the devotion of the daughters of Saint Vincent de Paul. He took refuge among them to escape his pursuers from among the insurgents. However, when he heard the death threats that these men made against these holy women he gave himself up to his furious pursuers despite the sisters' pleas. He was grabbed, forced to his knees, and was about to be executed. At this moment, the courageous superior ignored the threats of the malefactors and placed herself between them and their intended victim. She said to them: "This is the house of God, and you will not soil it by this crime! For 45 years I have served you, and for the first time I ask you for something in return. Can you refuse me?" Then one of these men put his bayonnet to the throat of another of the sisters and said: "Well then, it is you who will be killed." "Do you think I am afraid of your bayonette?" said the courageous virgin to him. She responded with disdain. "It is God alone that I fear." How can one not recoginze the divinity of a religion which engenders such sublime devotion!"