Partly. The Caisse des Dépôts publishes details annually of how centralised deposits are used (~60% of Livret A): ~57% go to social housing and thermal renovation, ~25% to infrastructure (water, transport, public facilities), with the rest going to various long-term loans. The non-centralised ~40% remain on distributing banks' balance sheets, used as conventional refinancing. Livret A is therefore partly transition-aligned, but is not a specific impact investment: for that, look at Livrets de Développement Durable et Solidaire (LDDS) with a donation option, or green bonds issued by the CDC.
Read the source article: Livret A, life insurance, PEA: what carbon footprint?