  The optical properties of the second generation dust that we observe in
debris disks remain quite elusive, whether it is the absorption efficiencies at
millimeter wavelengths or the (un)polarized phase function at near-infrared
wavelengths. Thankfully the same particles are experiencing forces that are
size dependent (e.g., radiation pressure), and with high angular resolution
observations we can take advantage of this natural spatial segregation.
Observations at different wavelengths probe different ranges of sizes, and
there is therefore a great synergy in multi-wavelength observations to better
constrain the optical properties of the particles. We present a new approach to
simultaneously model SPHERE and ALMA observations and apply it to the debris
disk around HD\,32297, putting the emphasis on the spatial distribution of the
grains with different $\beta$ values. This modeling approach requires few
assumptions on the actual sizes of the particles and the interpretation can
therefore be done a posteriori. We find that the ALMA observations are best
reproduced with a combination of small and large $\beta$ values ($0.03$ and
$0.42$) while the SPHERE observations require several intervals of $\beta$
values. We discuss the nature of the halo previously reported in ALMA
observations, and hypothesize it could be caused by over-abundant $\mu$m-sized
particles (the over-abundance being the consequence of their extended
lifetime). We model the polarized phase function at near-infrared wavelengths
and fluffy aggregates larger than a few $\mu$m provide the best solution.
Comparing our results with comets of the solar system, we postulate that the
particles released in the disk originate from rather pristine cometary bodies
(to avoid compaction of the fluffy aggregates) and are then set on highly
eccentric orbits, which could explain the halo detected at long wavelengths.
