She inherited Arthur Rimbaud's estate after his death in 1891 and became his literary executor.

Isabelle, like her siblings, grew up under the heel[1] of an authoritarian and conservative mother who instilled in her strict principles based on Christian morality.

She wrote down her brother's last letter [dictated] on 9 November 1891 and added his last words before the midday sun the following day.

She witnessed his great sufferings and was present during his death throes on the night of 9/10 November 1891.

She died on 20 June 1917, aged 57, of knee cancer (as her brother Arthur)[4] in Neuilly-sur-Seine, France.