A nice looking copy of "La flûte à six Schtroumpfs" is also available on eBay, this Johan & Pirlouit album was printed in 1960 and is considered to be the first Smurf appearance in a collected edition. The first standalone Smurf comic was printed in 1963 and was called "Les Schtroumpfs Noirs". This story can be found as a "mini-rêcit" in Spirou 1107, readers had to fold the middle pages of the issue and create their own mini version of "Les Schtroumpfs Noirs". So technically the first standalone Smurf comic appeared in 1959.
I recently found out this story wasn't released in the USA until 2011 because of the racist undertone, and they made the black Smurf purple. Tintin all over again
Spirou 1130, 1147, 1211, 1235, 1244, 2435 and 2438 each contain one of these little comics. In 1963 and later on they got printed as regular comics.