bˈɔːɹn ˌɔn fˈɪftiːn dʒuːlˈaɪ wˈʌn θˈaʊzənd sˈɛvənhˈʌndɹɪd fˈoːɹɾi wˈʌn ɪn pˈæɹɪs, hɪz fˈɑːðɚ wʌz sˈeɪsɑːɹ ˈæntɔɪn də lˌæ lˈuːzɚn, kˈɑːnt də bjˈuːzvɪl dˈaɪd wˈʌn θˈaʊzənd sˈɛvənhˈʌndɹɪd fˈɪfti fˈaɪv, ɐ mˈɑːɹɹeɪtʃəl də kˈæmp ɪnðə kˈɪŋz ˈɑːɹmi, ænd hɪz mˈʌðɚ wʌz mɚɹˈiːᵻlˈɪzəbəθ də lˈæmɔɪɡnən də blˈæŋkmɪsnˌɪl wˈʌn θˈaʊzənd sˈɛvənhˈʌndɹɪd sˈɪkstiːn wˈʌn θˈaʊzənd sˈɛvənhˈʌndɹɪd fˈɪfti ˈeɪt, ðə dˈɔːɾɚɹ ʌv lˈɔːɹd tʃˈænsɛlɚ lˈæmɔɪɡnən ænd ðə sˈɪstɚɹ ʌvðə sˈɛkɹətɹi ʌv stˈeɪt mˈeɪlʃɚbz.
Born on 15 July 1741 in Paris, his father was César Antoine de la Luzerne, comte de Beuzeville (died 1755), a Maréchal de camp in the king's army, and his mother was Marie-Elisabeth de Lamoignon de Blancmesnil (1716–1758), the daughter of Lord Chancellor Lamoignon and the sister of the Secretary of State Malesherbes.