YouTube has emerged as a major platform for political communication and news dissemination, particularly during high-stakes electoral periods. In the context of the 2024 European Parliament and French legislative elections, this study investigates how political actors and news media used YouTube to shape public discourse. We analyze over 100,000 video transcripts and metadata from 74 French YouTube channels operated by national news outlets, local media, and political figures. To identify the key themes emphasized during the campaign period, we applied a semi-automated method that combined large language models with clustering and manual review. The results reveal distinct thematic patterns across the political spectrum and media types, with right-leaning news outlets focusing on topics like immigration, while left-leaning emphasized protest and media freedom. Themes generating the most audience engagement, measured by comment-to-view ratios, were most often the most polarizing ones. In contrast, less polarizing themes such as video games and nature showed higher approval, reflected in like-to-view ratios. We also observed a general tendency across all media types to portray political figures in neutral or critical terms rather than favorable ones.

翻译：YouTube已成为政治传播与新闻分发的重要平台，在高风险的选举时期尤其如此。本研究以2024年欧洲议会选举及法国立法选举为背景，探讨了政治行为者与新闻媒体如何利用YouTube塑造公共话语。我们分析了来自74个法国YouTube频道的超过10万条视频转录文本及元数据，这些频道由全国性新闻机构、地方媒体及政治人物运营。为识别竞选期间被强调的关键主题，我们采用了一种半自动化方法，该方法结合了大型语言模型、聚类分析与人工审核。结果显示，不同政治光谱与媒体类型之间存在明显的主题模式：右倾新闻媒体侧重于移民等议题，而左倾媒体则强调抗议与媒体自由。以评论观看比衡量的受众参与度最高的主题，往往也是最具两极分化的主题。相比之下，电子游戏与自然等较少两极分化的主题表现出更高的认可度，这体现在点赞观看比上。我们还观察到，所有媒体类型普遍倾向于以中立或批判性而非赞许性的措辞描绘政治人物。