diff --git a/meteo-france/tropopause_inversion_and_mixing_length/condensation.F90 b/meteo-france/tropopause_inversion_and_mixing_length/condensation.F90
new file mode 100644
index 0000000..5de2268
--- /dev/null
+++ b/meteo-france/tropopause_inversion_and_mixing_length/condensation.F90
@@ -0,0 +1,114 @@
+!MNH_LIC Copyright 2002-2021 CNRS, Meteo-France and Universite Paul Sabatier
+!MNH_LIC This is part of the Meso-NH software governed by the CeCILL-C licence
+!MNH_LIC version 1. See LICENSE, CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt
+!MNH_LIC for details. version 1.
+!-----------------------------------------------------------------
+!     ######spl
+    SUBROUTINE CONDENSATION(D, CST, &
+        &PZZ, PT, PRC_IN, PRI_IN,  &
+        &OSIGMAS, &
+        &PLV, PLS, PCPH)
+
+!*       0.    DECLARATIONS
+!              ------------
+!
+USE MODD_DIMPHYEX,       ONLY: DIMPHYEX_t
+USE MODD_CST,            ONLY: CST_t
+
+!
+IMPLICIT NONE
+!
+!*       0.1   Declarations of dummy arguments :
+!
+!
+TYPE(DIMPHYEX_t),             INTENT(IN)    :: D
+TYPE(CST_t),                  INTENT(IN)    :: CST
+REAL, DIMENSION(D%NIJT,D%NKT), INTENT(IN)    :: PZZ    ! height of model levels (m)
+REAL, DIMENSION(D%NIJT,D%NKT), INTENT(INOUT) :: PT     ! grid scale T  (K)
+REAL, DIMENSION(D%NIJT,D%NKT), INTENT(IN)    :: PRC_IN ! grid scale r_c mixing ratio (kg/kg) in input
+REAL, DIMENSION(D%NIJT,D%NKT), INTENT(IN)    :: PRI_IN ! grid scale r_i (kg/kg) in input
+
+LOGICAL, INTENT(IN)                         :: OSIGMAS! use present global Sigma_s values
+                                   ! or that from turbulence scheme
+REAL, DIMENSION(D%NIJT,D%NKT), OPTIONAL, INTENT(IN)    :: PLV    ! Latent heat L_v
+REAL, DIMENSION(D%NIJT,D%NKT), OPTIONAL, INTENT(IN)    :: PLS
+REAL, DIMENSION(D%NIJT,D%NKT), OPTIONAL, INTENT(IN)    :: PCPH   ! Specific heat C_ph
+
+
+!*       0.2   Declarations of local variables :
+!
+INTEGER :: JIJ, JK, JKP, JKM                    ! loop index
+INTEGER :: IKTB, IKTE, IKB, IKE, IKL, IIJB, IIJE
+REAL, DIMENSION(D%NIJT,D%NKT) :: ZTLK           ! work arrays for T_l and total water mixing ratio
+REAL, DIMENSION(D%NIJT,D%NKT) :: ZL             ! length scale
+INTEGER, DIMENSION(D%NIJT)  :: ITPL             ! top levels of troposphere
+REAL,    DIMENSION(D%NIJT)  :: ZTMIN            ! minimum Temp. related to ITPL
+!
+REAL, DIMENSION(D%NIJT,D%NKT) :: ZLV, ZLS, ZCPD
+
+REAL :: ZLL, DZZ, ZZZ                           ! used for length scales
+
+REAL, DIMENSION(D%NIJT) :: ZDZ
+REAL :: ZPRIFACT
+
+
+REAL,PARAMETER :: ZL0     = 600.        ! tropospheric length scale
+
+
+------------------------------------
+!
+!
+!
+IKTB=D%NKTB
+IKTE=D%NKTE
+IKB=D%NKB
+IKE=D%NKE
+IKL=D%NKL
+IIJB=D%NIJB
+IIJE=D%NIJE
+
+ZPRIFACT = 1.    ! Initialize value
+
+IF(PRESENT(PLV) .AND. PRESENT(PLS)) THEN
+    ZLV(:,:)=PLV(:,:)
+    ZLS(:,:)=PLS(:,:)
+
+IF(PRESENT(PCPH)) THEN
+    ZCPD(:,:)=PCPH(:,:)
+
+! Preliminary calculations needed for computing the "turbulent part" of Sigma_s
+IF ( .NOT. OSIGMAS ) THEN
+    DO JK=IKTB,IKTE
+        DO JIJ=IIJB,IIJE
+! store temperature at saturation
+            ZTLK(JIJ,JK) = PT(JIJ,JK) - ZLV(JIJ,JK)*PRC_IN(JIJ,JK)/ZCPD(JIJ,JK) &
+                 - ZLS(JIJ,JK)*PRI_IN(JIJ,JK)/ZCPD(JIJ,JK)*ZPRIFACT
+        END DO
+    END DO
+! Determine tropopause/inversion  height from minimum temperature
+    ITPL(:)  = IKB+IKL
+    ZTMIN(:) = 400.
+    DO JK = IKTB+1,IKTE-1
+        DO JIJ=IIJB,IIJE
+            IF ( PT(JIJ,JK) < ZTMIN(JIJ) ) THEN
+                ZTMIN(JIJ) = PT(JIJ,JK)
+                ITPL(JIJ) = JK
+            ENDIF
+        END DO
+    END DO
+    ! Set the mixing length scale
+    ZL(:,IKB) = 20.
+    DO JK = IKB+IKL,IKE,IKL
+        DO JIJ=IIJB,IIJE
+            ! free troposphere
+            ZL(JIJ,JK) = ZL0
+            ZZZ =  PZZ(JIJ,JK) -  PZZ(JIJ,IKB)
+            JKP = ITPL(JIJ)
+            ! approximate length for boundary-layer
+            IF ( ZL0 > ZZZ ) ZL(JIJ,JK) = ZZZ
+            ! gradual decrease of length-scale near and above tropopause
+            IF ( ZZZ > 0.9*(PZZ(JIJ,JKP)-PZZ(JIJ,IKB)) ) &
+                ZL(JIJ,JK) = .6 * ZL(JIJ,JK-IKL)
+        END DO
+    END DO
+END IF
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diff --git a/meteo-france/tropopause_inversion_and_mixing_length/condensation.md b/meteo-france/tropopause_inversion_and_mixing_length/condensation.md
new file mode 100644
index 0000000..23e46af
--- /dev/null
+++ b/meteo-france/tropopause_inversion_and_mixing_length/condensation.md
@@ -0,0 +1,17 @@
+In this example, the turbulent mixing scale is computed according to the distance of the layer to the
+tropopause.
+
+- l91 to l98 : the vertical index _JK_ of the tropopause level is retrieved from temperature inversion and stored in _ITPL(IJ)_ 
+- l101 to 113 : the mixing length _ZL_ is computed according to height of the tropopause _PZZ(IJ, JKP)_ 
+
+
+Indices conventions are the following :
+- IKL : order of the vertical levels
+    1 if level are numbered from ground to space
+    -1 if level are numbered from space to ground
+- IKB : nearest level to the ground
+- IKE : nearest level to the space
+- IKTB is IKB + padding
+- IKTE is IKE + padding
+
+In this case, loop at l101 is always executed from ground to space
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