Melchior Leroux

The provided news articles do not contain any information about a person named Melchior Leroux. Therefore, it is impossible to provide a summary of their background, newsworthiness, recent events, or current relevance based on the given text. The articles discuss Céline Dion's potential return to the stage, a former Lido costume designer facing trial for sexual assault allegations, and a national tribute to former Prime Minister Lionel Jospin. None of these topics relate to an individual named Melchior Leroux.