Question: Who was the french conspirator who killed the last french monarch in 1574?

Context paragraphs:
Louis XVI style: Louis XVI style, frequently also called Louis Seize, is a characteristic French style in art, architecture, and decorative motif which developed during the 19-year reign of the French monarch Louis XVI (1774–1793) though it often thought to encompass nearly twice that many (1750-1800).  It saw the final phase of Rococo-style art as well as the birth of French neoclassicism and the Directoire style which followed it: whereas Rococo has become labeled as overdone and gawdy with its constant use of symmetric flourishes and excessive precise decoration, neoclassicism sought to evoke the artistic styles that were just then being rediscovered in Herculaneum and Pompeii: the straight column, the simplicity of the post-and-lintel, the architrave of the Greek temple, etc., as well as the Rousseau-inspired values of returning to nature and the view of nature as an idealized and wild but still orderly and inherently worthy model for the arts to follow.

Henry IV of France: Henry IV (French: "Henri IV" , read as "Henri-Quatre" ] ; 13 December 1553 – 14 May 1610), also known by the epithet "Good King Henry", was King of Navarre (as Henry III) from 1572 to 1610 and King of France from 1589 to 1610.  He was the first French monarch of the House of Bourbon, a branch of the Capetian dynasty.

Jacques Clément: Jacques Clément (1567 – 1 August 1589) was a French conspirator and the killer of king Henry III.

List of the last monarchs in the Americas: The Native American hereditary leaders during this time are not included.  Those that are listed as former monarchs of what is now the continental United States were heads of European seated monarchies (or Mexican monarchs, such as Agustín I of Mexico and Maximilian I of Mexico) and themselves never set foot on American soil.  Others were indigenous monarchs, such as Malietoa Tanumafili I, Tuʻi Manuʻa Elisala and Liliuokalani of Hawaii; The last monarch of each state and territory may not be the last colonial ruler (i.e. Louis XV of France is the last French monarch of Louisiana, but Napoleon Bonaparte, prior to becoming Emperor, was the last ruler of Louisiana).  Also their end of reign may not be how the US acquired these states.  One state can have more than one last monarch, since each state may have been the product of many different acquisitions by the United States.  Different claims of a foreign country are taken into account.

Henry III of France: Henry III (19 September 1551 – 2 August 1589; born "Alexandre Édouard de France", Polish: "Henryk Walezy" , Lithuanian: "Henrikas Valua" ) was King of the Polish-Lithuanian Commonwealth from 1573 to 1575 and King of France from 1574 until his death.  He was the last French monarch of the House of Valois.

Jus exclusivae: Jus exclusivæ (Latin for "right of exclusion"; sometimes called the papal veto) was the right claimed by several Catholic monarchs of Europe to veto a candidate for the papacy.  The French monarch, the Spanish monarch, the Holy Roman Emperor, and the Emperor of Austria claimed this right at various times, making known to a papal conclave, through a crown-cardinal, that the monarch deemed a particular candidate for the papacy objectionable.

Philip II of France: Philip II, known as Philip Augustus (French: "Philippe Auguste" ; 21 August 1165 – 14 July 1223), was King of France from 1180 to 1223, a member of the House of Capet.  Philip's predecessors had been known as kings of the Franks, but from 1190 onward, Philip became the first French monarch to style himself king of France.  The son of King Louis VII and his third wife, Adèle of Champagne, he was originally nicknamed "Dieudonné" "God-given" because he was the first son of Louis VII, born late in his father's life.  Philip was given the nickname "Augustus" by the chronicler Rigord for having extended the Crown lands of France so remarkably.

Coronation of the French monarch: The accession of the King of France was legitimized by coronation ceremony performed with the Crown of Charlemagne at Notre-Dame de Reims.  However, the person did not need to be crowned in order to be recognized as French monarch; the new king ascended the throne when the coffin of the previous monarch descended into the vault at Saint Denis Basilica, and the Duke of Uzes proclaimed "Le Roi est mort, vive le Roi"!

Biette de Cassinel: Biette Cassinel (1340-1380), was the royal mistress of Charles V of France, from 1360 until 1380.  She has been referred to as the first official mistress of a French monarch.

Battle of Soissons (923): The Battle of Soissons in 923 was a battle during which King Robert I of France was killed, possibly by King Charles III (by legend in single combat), and the latter was defeated and imprisoned by Rudolph, Duke of Burgundy who succeeded Robert I as French monarch.

Supporting paragraphs: Jacques Clément Henry III of France
Answer: Jacques Clément