She said she had questioned "on the meaning of [her] belonging to La République En Marche since the departure of Nicolas Hulot from the government", and had "a click" while speaking to the Assembly, without having premeditated, against an amendment, tabled by surprise, reducing by 15 million euros the budget of state medical aid.

[9] In 2019, de Temmerman joined an international group of parliamentarians in a joint call for a body to strengthen the democratic representation of the world's citizens in global affairs and the UN's decision-making.

[10] In July 2019, de Temmerman decided not to align with her parliamentary group's majority and became one of 52 LREM members who abstained from a vote on the French ratification of the European Union’s Comprehensive Economic and Trade Agreement (CETA) with Canada.

[11] In November 2019, de Temmerman denounced the government's new immigration plan and declared in the National Assembly: "Are we going this morning, I tell you, to complete humanism?

She co-signed a platform with ten other LREM deputies to oppose the government's measures on immigration concerning health and especially state medical aid (AME), pleading not to give in to urgency and ease ».