This research presents a comprehensive comparative study of the problematic "Real Estate Transaction between Consensualism and Formality," aiming to reveal the methodological divergence between Iraqi and French laws in handling the transfer of real estate ownership. The research problem centers on the conflict between the principle of "Consensualism," based on the autonomy of will, and "Formality," imposed by legislation as a guarantee for legal certainty and transaction stability. The study adopted a comparative analytical approach to deconstruct the dialectic between these two principles. It concluded that the Iraqi legislator adopted absolute "Constitutive Formality," making registration in the Real Estate Registration Department a fundamental pillar without which the contract is not formed. Conversely, the French legislator maintained "Consensualism" as the general rule for transferring ownership between parties, viewing formality (notarization and registration) as a means for the transaction's opposability to third parties. The research reached significant results, most notably that the formal strictness in Iraqi law may sometimes lead to the loss of contractual justice, necessitating judicial intervention through the "Contract Conversion" theory to safeguard rights. The study concluded with recommendations urging the Iraqi legislator to benefit from the French experience by separating "contract formation" from its "opposability to third parties," to enhance the flexibility of real estate circulation while maintaining registration requirements.