Oh no, let me guess - she was actually Polish? LOL
Sorry, no idea but she was very very popular in many countries, particularly in Poland - I think.
It still seems a bit odd but similar things do happen in other countries.
I very doubt "it's in celebrity alley" will be regarded as the answer the OP is looking for.
Try again (if you can grasp the intention of the question)
Kielce used to be a black hole of Universe - with beautiful surroundings but unfortunately with rotten downtown. I hear a lot about big transformation taking place in Kielce in the past decade or so: new infrastructure, clean streets and parks, new cultural institutions, new international centres, etc. One of such initiatives there is so-called "Avenue of Stars" - with busts of famous people - both Polish and international.
The "Avenue of Stars" includes the following busts: Andy Warhol (artist), Czeslaw Niemen (musician), Edith Piaf (singer), Franz Kafka (writer), Galina Lancers (dancer), George Gershwin (pianist, composer), Ignatius Paderewski (pianist, composer), Igor Stravinsky (Composer), James Joyce (writer), Jimi Hendrix (musician), Joseph Conrad (writer), Karol Szymanowski (Composer), Krzysztof Kieslowski (director), Marc Chagall (painter), Mark Grechuta (musician, composer, singer, poet), Maria Pawlikowska-Jasnorzewska (writer) Mikhail Bulgakov (writer), Olga Boznanska (painter) Pablo Picasso (painter), Stanislaw Ignacy Witkiewicz (painter, poet), Tadeusz Kantor (director ), Tamara de Lempicka (painter), Witold Gombrowicz (Author), Witold Lutoslawski (Composer), Zbigniew Herbert (poet), Dmitri Shostakovich (Composer), Stanislaw Lem (writer), Ingmar Bergman (film director), Krzysztof Kamil Baczynski (poet ), Salvador Dali (painter), Bulat Okudzhava (poet, writer).
So Edith Piaf is one of many stars celebrated there - but there is no particular relation between her and Kielce.