  According to the current paradigm of galaxy formation, the first galaxies
have been likely formed within large dark matter haloes. The fragmentation of
these massive haloes led to the formation of galaxy protoclusters, which are
usually composed of one to a few bright objects, surrounded by numerous fainter
(and less massive) galaxies. These early structures could have played a major
role in reionising the neutral hydrogen within the first billion years of the
Universe; especially, if their number density is significant.Taking advantage
of the unprecedented sensitivity reached by the \textit{James Webb Space
Telescope (JWST)}, galaxy protoclusters can now be identified and studied in
increasing numbers beyond $z\geq\ $6. Characterising their contribution to the
UV photon budget could supply new insights into the reionisation process. We
analyse the first JWST dataset behind SMACS0723-7327 to search for
protoclusters at $z\geq6$, combining the available spectroscopic and
photometric data. We then compare our findings with semi-analytical models and
simulations. In addition to two bright galaxies ($\leq$26.5 AB in F277W),
separated by $\sim$11\arcsec and spectroscopically confirmed at
$z_{spec}=7.66$, we identify 6 additional galaxies with similar colors in a
$\theta\sim20$\arcsec radius around these (corresponding to R$\sim60-90$ kpc in
the source plane). Using several methods, we estimate the mass of the dark
matter halo of this protocluster, $\sim$3.3$\times$10$^{11}$M$_{\odot}$
accounting for magnification, consistent with various predictions. The physical
properties of all protocluster members are also in excellent agreement with
what has been previously found at lower redshifts: star-formation main sequence
and protocluster size. This detection adds to just a few protoclusters
currently known in the first billion years of the universe.
