No, they are NOT interchangeable. "上级对下级用敦促" (used by people when speaking to their underlings) is also incorrect. Nowadays 敦促 means urging someone/some authority to *do* something. 催促 is more about urgency in time, and is usually usually between persons, say A wants B to do/finish something sooner. So, for "the manager urges Wang to finish his task as soon as possible", we say 经理催促小王尽快完成任务 in a word, 敦促 is saying "do it!" 催促 is saying "do it fast!" (Sorry I don't speak French, otherwise I would have answered in your language)

諸多回答中 唯有YoshiYoshi 以及 ivy 對於 敦促 一詞 有觸及核心之論 敦 之動詞意義 是 和睦、使融洽 如「敦親睦鄰」 形容詞意義是 質樸 篤厚 如「敦厚」 副詞之意義是 誠懇 如「敦聘」「敦請」 均隱含 平和 平等 圓融 之意義 故無關乎 上下級 尊卑關係 或者書面口語 至於 Zhang Rui 所言 基於 法律之前 人人平等之概念 故用 敦促 一詞

敦促is very formal and, official; 催促, is more widely used.

if friends,or some common peole,you can say"催促“ if a counrty,for example.中國敦促越南儘早撤出南沙群島。

敦促比较书面,往往用于外交场合.催促口语化,而且往往用于关系较近的人之间.