The primary purpose of this study is to assess the efficacy and safety of daily DBV712 250 micrograms (mcg) to induce desensitization to peanut in peanut-allergic children 4-7 years of age over a 12-month double-blind, placebo-controlled (DBPC) Treatment Period.

This study is consisting of a 4-week Screening Period, 12-month DBPC Treatment Period and an open-label extension of either 24 or 36-months duration so that each participant may have the opportunity to receive DBV712 for a total duration of 36 months. Following 36 months of treatment with DBV712 250 mcg, sustained unresponsiveness (SU) will be evaluated by subsequent open food challenge(s) [FC(s)] at 2-, 4-, and 6-months off treatment.

Maximum participant participation will be either approximately 44 or 56 months, depending on the participant's randomized treatment assignment. During the 4-week Screening Period, participants are required to meet 2 sequential screening parameters to determine eligibility prior to randomization:

• Assessment of peanut skin prick test (SPT) and serum peanut immunoglobulin-E (IgE)
• Peanut double-blind placebo-controlled food challenge (DBPCFC) to confirm peanut allergy and establish an entry peanut eliciting dose (ED). Participants with a peanut protein ED less than or equal to (≤) 100 milligram (mg) will be eligible for randomization.

The starting dose of the eligibility peanut DBPCFC will be 1 mg peanut protein and will escalate up to a highest single dose of 100 mg peanut protein (cumulative 144 mg) via the following schedule: 1, 3, 10, 30, 100 mg. Participants who react, with an eliciting dose (ED) (with dose-limiting symptoms) at or below the dose of 100 mg peanut protein will be considered eligible.

Randomization of eligible participants will occur in a 2:1 ratio to DBV712 250 mcg (active treatment) or placebo, respectively.

Key Inclusion Criteria:

• Aged 4 through 7 years at Visit 1 (screening).
• Physician-diagnosed peanut allergy or children with a well-documented medical history of IgE-mediated reactions after ingestion of peanut and currently following a strict peanut-free diet.
• Peanut-specific IgE of >0.7 kilo allergy unit per liter (kUA/L) and a positive peanut SPT with the largest wheal diameter of ≥6 millimeter (mm) at Visit 1.
• An ED of ≤100 mg peanut protein at screening DBPCFC.

Participants may enter the Open-label Extension Period if they meet all of the following inclusion criteria:

• Signed ICF by the participant's parent(s)/caregiver(s). This consent should be signed after completion of the procedures in the randomized, DBPC Treatment Period, and before any procedure in Open-label Extension Period begins.
• Participants who perform the peanut DBPCFC at the end of Month 12 and have ≥80% compliance with investigational medicinal product (IMP).
• Parent(s)/caregiver(s) and participants willing to comply with all study requirements during the participant's participation in the study.

Key Exclusion Criteria:

• Severe generalized dermatologic disease involving the application area (interscapular region)
• Uncontrolled persistent asthma.
• Past or current immunotherapy for peanut allergy, including oral immunotherapy (OIT).
• Current immunotherapy for any allergen (including food allergy, allergic rhinitis and/or insect allergy), or treatment with any monoclonal antibody or biologic immunomodulatory therapy within 6 months prior to Visit 1.

Participants may not enter the Open-label Extension Period if they meet any of the following exclusion criteria:

• Participants who develop a severe anaphylactic reaction during the DBPCFC at the end of Month 12 with the event requiring tracheal intubation or leading to a cardiac arrest and/or to coma. Participants with other reported cases of severe anaphylaxis will be considered eligible to participate in the Open-label Extension Period, at the judgement of the Investigator.
• Any clinically significant disease which in the judgment of the Investigator may preclude safe participation or strict compliance with the protocol procedures.